I will be retiring the Broken Symmetry blog from Typepad soon. At least for now, the posts will be available on Wordpress. Longer term, I'll have a presence at symmetrybroken.com But that site is not yet live.
We brought Maxwell’s 1861 model of a magnetic line of force up to date using modern knowledge of polarised waves and of experiments on quantised magnetic flux. Our model obeys the equations for Euler’s fluid and supports light-like solutions which are polarised, absorbed discretely, consistent with the Bell tests, and obey Maxwell’s equations to first order.
I can't quite see what would serve as the driving oscillation for electrons. I guess here the authors argue that it could be quasiparticle spin synchronization.
In 2005, Furusawa et al. reported log-normal distributions in protein concentration in bacteria, and showed how these log-normal distributions might arise from Brownian dynamics. Not all cell characteristics arise from Brownian dynamics (i.e., multiplicative stochastic dynamics with a linear noise term) or exhibit log-normal distributions. For example, cell size distributions appear to arise from Langevin dynamics (i.e., multiplicative stochastic dynamics with a sublinear noise term) and produce distributions that remain stationary in time. See this work, for example. But based on Furusawa et al., it seems reasonable to predict that the cellular concentration of a protein like ATP synthase might obey Brownian dynamics.
As pointed out recently in a paper from Ole Peters and Alexander Adamou, Brownian dynamics have some interesting statistical properties. In particular, ergodicity is broken because the log-normal distributions that arise from Brownian dynamics are not stationary. Rather, over time the size of fluctuations (the variance) increases as the square-root of time. This asymmetry in time can be rather subtle because it's a difference in variance that grows at a sublinear rate. If the variance is large relative to the mean, it can take a lot of measurements (and often a long time) to be sure you're seeing a difference in variance and rule out the possibility that your distribution is stationary.
But when Brownian dynamics are present, there are potentially some interesting consequences. For example, as Peters and Adamou suggest, if we model "cooperation" between two entities (like intracellular organelles?) as the sharing and mixing of what would otherwise be two independent populations (or concentrations of a chemical?), we see a damping or smoothing in the fluctuations (the variance). As time goes on, the cooperating populations grow faster in concentration than wholly independent populations thanks to that damping effect. See Figure 2:
Abstracted away from the details, we have Brownian dynamics and an opportunity for "cooperation" (i.e., mixing or sharing) leading over time to faster growth rates (e.g., in a concentration of proteins or chemicals) through a cooperative damping of fluctuations in concentrations of the same proteins or chemicals. Kind of nice to see how simple assumptions like these could lead to evolutionary dynamics.
Thinking about closing this blog -- I'm down to one post a year! Here's a list of best books read in 2015. Again, no particular order
Andreas M. Antonopoulos
Shuji Nakamura was one of three who shared the Nobel in Physics this week.
Prof. Nakamura, who now teaches at UCSB, was also the plaintiff under Article 35 of the Japanese Patent Act against his former employer Nichia. Article 35 provides a right to reasonable compensation for inventors. The court of original jurisdiction awarded almost $200 million to Prof. Nakamura before the case settled while an appeal was pending for $8 million. See the excellent summary here.
To most people, capital means a bank account, a hundred shares of IBM stock, assembly lines, or steel plants in the Chicago area. These are all forms of capital in the sense that they are assets that yield income and other useful outputs over long periods of time.
But such tangible forms of capital are not the only type of capital. Schooling, a computer training course, expenditures on medical care, and lectures on the virtues of punctuality and honesty are also capital. That is because they raise earnings, improve health, or add to a person’s good habits over much of his lifetime. Therefore, economists regard expenditures on education, training, medical care, and so on as investments in human capital. They are called human capital because people cannot be separated from their knowledge, skills, health, or values in the way they can be separated from their financial and physical assets.
- Gary Becker on "Human Capital" at the Library of Economics and Liberty
Social media is, in effect, the administration and organization of people, similar to what businesses, governments, institutions, and religious organizations do in worlds offline. The software industry has, however, been generally skeptical of comparing its work with anything that might resemble a political, cultural, or spiritual process, due to its self-image as a secular and “scientific” enterprise.Recently, Larry Lessig and others have compared law to source code. The analogy is compelling for a variety of reasons. But one not necessarily emphasized is that the analogy may actually be exact when run in reverse — i.e., code is law. The analogy works not merely because when organizations carry out procedures and implement rules embodied in law they are like machines processing source code, but because the procedures and rules codified (!) in law reflect the culture of an organization. That is not a new idea. In The Common Law (1902), Holmes recognized that "The life of the law has not been logic: it has been experience." But it is a profound and deeply subversive one in a world being eaten by software.
Two years ago, we did a program about a mysterious business in Texas that threatens companies with lawsuits for violating its patents. But the world of patent lawsuits is so secretive, there were basic questions we could not answer. Now we can. And we get a glimpse why people say our patent system may be discouraging, not encouraging, innovation.
NPR did a good job here overall, although the story is told from a naive and skeptical view of the patent system. There were a couple of things hinted at in the story, which I really like. First there is the suggestion (made express in a few places) that license terms ought not to be so private. I agree with this, and Nathan Myhrvold and Mark Lemley even suggested that more public disclosure would be necessary for a thicker market in patent rights to develop. Historically, corporate charters and patents have the same origin. Corporate charters that have a wide public impact are subject to also sorts of reporting requirements now (SOX, SEC, etc.). Why shouldn't patents that have such a wide public impact be subject to the same disclosure requirements? It's no answer to say that this would put licensors at a competitive disadvantage so long as the same rules applied to everybody. Too bad IV isn't leading in this regard instead of getting dragged kicking and screaming into more transparency.
Second, there is the suggestion (again made express in a few places, especially in description of the cotton gin) that patents enable dissemination of knowledge in ways beyond simply public disclosure of their specification. Critics of the patent system are after a red herring when they focus attention on the dubious quality of specifications as enabling. The social value of a specification is primarily found in what it provides as evidence of what was known by inventors (and their employer) as of a certain point in time. This aspect of the social value of patents is best understood within the asset partition theory framework advanced by Paul G. Heald (within the larger theory presented by Hansmann and Kraakman).
See also the official public response from IV here.
I'm intrigued by the way crowdsourced funding is upsetting the balance of power in financing new films, and companies. The basic trend is toward less and less friction (or what Coase calls "transaction costs") in obtaining financing. At the limit, we have perfectly efficient financing in which ideas receive funding up to the opportunity cost of capital (i.e., up to the next best startup or film that could have been funded). Five years ago, things looked grim thanks to the costs of SOX and the resulting shift of new listings overseas. Technology to the rescue! Gives warm fuzzies to those who tend to be more pessimistic.
But is there less friction for inventors and patentees? Maybe a little, but not the dramatic shift we've seen in private equity financing. And why not? Here things get murky. Looking at equity financing, we can see that at least part of the reason crowdsourced financing has taken off is because of the new "exit" opportunities it offers. At least in relative terms, people prefer what they get from contributing on kickstarter to watching their money go down the tubes in a Facebook IPO. Are there new exit opportunities for inventors and patentees? Nope. It's the same exit opportunities that have always been there. So is there less friction? Maybe a little less. But without the new exit opportunities, it's unclear whether what appears to be reduced friction for inventors and patentees is, in fact, improved allocative efficiency, or whether instead it's an opportunistic redistribution of wealth. We shall see.
Regardless, it's worth asking: if we could dramatically reduce the friction for inventors and patentees, would the public at large view the patent system as more effective or less effective at its goal of promoting innovation? The answer, I think, depends not on whether friction is reduced, but how. It seems to me that there is simply no (lasting) benefit to any stakeholder in the patent system to reducing the friction in reallocations of ownership until the friction in exits can be reduced even further. Universities avoid the problem by limiting the intake to their pipeline, which is wiser than clogging it up with inventory that goes stale. What's the new exit? That's the billion dollar question to be answered by anybody with an interest in seeing the patent system evolve.
we have explicitly proposed a novel physical connection between adaptive behavior and entropy maximizationThey get some pretty interesting results from some parsimonious assumptions. See also this earlier post linking to the work by Kaila and Annila on the Principle of Least Action and the Second Law.
I have to say that as I look at the plots above, I’m struck by their similarity to plots for physical processes like chemical reactions. It’s as if all those humans, with all the complexities of their lives, still behave in aggregate a bit like molecules—with certain “reaction rates” to enter into relationships, marry, etc.
This paper provides a tractable theoretical framework for the study of the economic forces shap- ing the relationship between the structure of the financial network and systemic risk. We show that as long as the magnitude (or the number) of negative shocks is below a critical threshold, a more equal distribution of interbank obligations leads to less fragility. In particular, all else equal, the sparsely connected ring financial network (corresponding to a credit chain) is the most fragile of all configura- tions, whereas the highly interconnected complete financial network is the configuration least prone to contagion. In line with the observations made by Allen and Gale (2000), our results establish that, in the more complete networks, the losses of a distressed bank are passed to a larger number of counterparties, guaranteeing a more efficient use of the excess liquidity in the system in forestalling defaults.
We also show that when negative shocks are larger than a certain threshold, the second view on the relationship between the structure of the financial network and the extent of contagion prevails. In particular, completeness is no longer a guarantee for stability. Rather, in the face of large shocks, financial networks in which banks are only weakly connected to one another would be less prone to systemic failures. Such a “phase transition” is due to the fact that, the senior liabilities of banks, as well as the excess liquidity within the financial network, can act as shock absorbers. Weak interconnections guarantee that the more senior creditors of a distressed bank bear most of the losses and hence, protect the rest of the system against cascading defaults.
The model of cash-flow among the banks (see equation 1 at section 2.4) has at least some superficial similarities to a 2-D Ising Model, and the authors could probably capture the dynamics they're modeling with an even more parsimonious model than they've given in this paper. But it's encouraging to see economists moving in this direction. See An Economy Made of Glass.
On a not unrelated-note, they solve for equilibrium here with Brouwer's Fixed Point Theorem. I am aware of a historical explanation for this, but it still surprises me to see models being set up to be solved this way given the instrumental challenge of testing the same models with empirical data. I have an ongoing and unfulfilled wish to see folks like Acemoglu et al. take the time to meet and discuss their models with folks like Jon Kleinberg and Steve Strogatz at Cornell. Economists just don't seem to be getting enough leverage out of the more recent applied math on networks or glass transitions.
The two-player Iterated Prisoner’s Dilemma game is a model for both sentient and evolutionary behaviors, especially including the emergence of cooperation. It is generally assumed that there exists no simple ultimatum strategy whereby one player can enforce a unilateral claim to an unfair share of rewards. Here, we show that such strategies unexpectedly do exist. In particular, a player X who is witting of these strategies can (i) deterministically set her opponent Y’s score, independently of his strategy or response, or (ii) enforce an extortionate linear relation between her and his scores. Against such a player, an evolutionary player’s best response is to accede to the extortion. Only a player with a theory of mind about his opponent can do better, in which case Iterated Prisoner’s Dilemma is an Ultimatum Game.Personally, I kind of enjoy living in a world in which a fundamental "truths" about things as abstract and oversimplified as the prisoners' dilemma can turn out to be incorrect for so long. Still trying to understand and wrap my head around these results.
A key assumption of today’s standard account of patents is that, absent patent protection, all products would generally be purchased in a competitive market. However, the first regularized patent system appeared during the Renaissance in the Venetian Republic, which was a highly regulated economy. In the Venetian economy, many types of products - particularly, artisanal or technological products - could typically be produced and sold only by artisan and merchant guilds. One important exception to the guilds’ monopolies were 'patents,' which initially provided non-guild members - particularly foreigners - the privilege of being able to sell products and practice methods that were otherwise within the sole province of the guilds. Directly contrary to the view that patents tend to diminish competition, patents in the Venetian Republic enabled a new kind of competition from outside of the guild system. This article explores the role patents played in promoting competition in the Venetian Republic. This exploration is important for understanding not only the historical genesis of the patent system, but also in gaining a deeper understanding of the patent system today.
SSRN link here.
According to their account, the patent system in Venice was setup initially to give talented foreigners a chance at competing with the entrenched guilds. The same agency responsible for immigration was also responsible for examining and granting patents.
Meanwhile, in Silicon Valley, we're sending talented immigrants home after we're done educating them.
As a culture, why shouldn't we be equally concerned with answering a related question -- i.e., have corporations, and especially their R&D groups, gotten close enough to Universities? I take it nobody would have any concern if corporate R&D groups were to become more open in publishing their results, disseminating their knowledge, and even teaching new engineers and scientists.
The poorly kept secret is that there aren't anymore corporate R&D labs like that. Bell Labs is gone. IBM labs are not what they used to be. So Stanford has stepped in to fill the gap. Should we be mourning the loss of its pure curiosity-driven culture -- a culture that probably never existed at Stanford anyway? No there are other universities that do that better. Note that Gerhard Casper, quoted in a few places in the article, hails from Chicago.
It's not wise to pass judgement on Stanford's culture without considering how it fits within the larger ecosystem.
So a typical company in manufacturing might do 8 inventory turns. Samsung does 17. Dell, which practically invented hardcore electronics supply chain management, does 36. Apple is doing 74!Click through to Gartner to get the full report.
The time has come to enact national legislation that provides clear record title to patent applications and patents. The value of patents is too great to continue with the present system. Moreover, patents are a federal right and should be addressed at a federal level. A national system would harmonize U.S. law with those of other countries, which generally have a national system for recordation of patent rights. Recently, the Patent Office proposed rules that would require disclosure of any assignee of patent rights. But these rules simply do not go far enough. Legislation is necessary in order to provide a comprehensive internationally recognized system that assures the recordation of patent title, security interests, and other encumbrances through filings solely in the Patent Office.See also Patent Reform through the Creation of Economic Facts. A few years ago, I suggested here that an econometric analysis of patented features that focused on frequency-averaged measures of sales and manufacturing might be useful as a mechanism for valuing patents. That is way too complicated to be workable right now at least. But with reliable information about ownership and prior licensing of a portfolio available, comparable-based patent valuations would become more feasible for the many market participants who do not come with their own private database of such information.
The last bit brings to mind Franklin's reply to the woman who asked him, immediately after the Constitutional Convention adjourned, what kind of government had they had given us. I guess we've done alright by Franklin so far.
But here is the irony. All this high‐toned government, the unelected and long‐termed Governors of the Federal Reserve, supported by Senators and Representatives serving for decades these establishment figures are the ones who have created the current mess. They did nothing to curb budget deficits or to reform entitlements when it might have been done less painfully. They wallowed in earmarks and budget gimmickry, set unrealistically low interest rates, borrowed ever‐increasing sums of money to satisfy current expenses, and made promises that are unsustainable but somehow never get contained. And it is the placard‐waving, Jeffersonian common horde flocking to town halls and filling town squares, who have become the champions of Hamiltonian concern for the long run: “Spend less, tax less and borrow less,” they say. Bring back the Hamiltonian dream, where penniless bastards from nowhere can rise by the sheer force of intellect, hard work, and audacity to succeed in an America that prefers opportunity to entitlement, that lets losing businesses fail, and winning businesses make serious money.
How ironic it will be if Hamilton’s dream of a national blessing were restored by the very low‐toned, democratic, unruly politics that he thought incapable of it.
How much would you pay to play a game in which a coin was flipped, and each time it landed heads the payout was doubled from a starting value of $1? The expected value of this game is not finite, and yet most people are not willing to pay more than a few bucks for it, much less borrow to play.
This is the so-called St. Petersburg Paradox. The earliest solution was proposed by Bernoulli, who suggested that the value people attached to their wealth went as a logarithmic rather than linear function of increasing wealth. Given that assumption, he calculated the amount a person should be willing to wager as log(change in wealth due to payout from lottery) - log (wealth - wager).
But this calculation is not quite correct even though it resolves the paradox by explaining why most people won't wager much: People won't wager much because that logarithm runs off to infinity fast as the wager approaches even a fraction of wealth -- producing a zero in the denominator.
One way to see that this calculation is incorrect is because it treats the wager as a static cost, existing independent of how the payoff increases with increasing flips. Another way to say the same thing is that the wager has time-value in the form of interest. So the expected value and the wager should be treated together in the utility function in successive flips of the coin. What you should wager depends not just on how much, but when the payoff comes.
Ole Peters tells the full story of the St. Petersburg Paradox, including the errors in its analysis later introduced by economist Karl Menger, and propagated by Arrow and Samuelson, in glorious detail here.
I am grateful to Rick Bookstaber for pointing me to the paper.
"So what?" you might ask. Well, if one gets into the habit of treating economic variables as time-series rather than ensemble averages -- as the correction demands -- then one immediately is forced out into the realm of non-equilibrium statistical mechanics and dynamics.
Ole Peters and Alexander Adamou have already proposed a correction to EMH. According to them, it is not prices that are efficient and cannot be arbitraged, but rather the use of leverage to produce larger than logarithmic gains.
I'm completely drowning in patent litigation right now, but eventually I would like to offer some thoughts on what these papers mean for competition and innovation policy. What should be considered analogous to leverage in intellectual property markets?
The potential implications for investors are also interesting and need to be thought through. Do we now have a quantitative insight into how and why so many of the investors who have consistently beat the market over the past few decades have advised against leverage. Buffett, in particular, is famous from eschewing leverage and advising others to do the same.
Section 3. First Inventor to File
Amends 35 U.S.C. § 102 to redefine prior art as anything patented, published, on sale, or in public use before filing, or any patent application filed by another before the effective filing date of the claimed invention.
Eliminates most interference proceedings. (Derivation proceedings for allegedly copied remain available.)
18-months after the date of enactment, applying to any patent filed or claiming priority to a patent filed thereafter
Clients have six months after enactment to educate inventors about the elimination of the 1-year grace period, and need to get a patent application on file.
Section 4. INVENTOR'S OATH OR DECLARATION
Amends 35 U.S.C. § 115 to permit applicants to make a "substitute statement" in lieu of an oath or declaration when an inventor is deceased, under legal incapacity, or cannot be found or reached after diligent effort."
Amends 35 U.S.C. § 118 to permit applicants to apply on behalf of inventors when "the inventor has assigned or is under an obligation to assign." Until now, applicants were permitted to apply on behalf of an inventor only when the inventor could not be found or reached after diligent effort.
One year after the date of enactment, applying to any patent application filed on or after that date
Section 4 will streamline the process of obtaining oaths or declarations, a process which under the current rules has been a hassle, especially in locating former employees upon the filing of continuations or divisionals of an original application.
Section 5. Prior COMMERCIAL Use DEFENSE
This section expands the prior user defense under 35 U.S.C. § 173, currently is available only for business method patents, to all patents.
The prior user bears the burden of showing a prior use of the claimed invention more than a year before the priority date of the claimed invention. Such prior uses would be a valid defense even if kept confidential.
The defense is personal to the prior user and non-transferable except for transfers of an entire enterprise or line of business, and then only for prior uses at the same site.
The defense is unavailable to prior users when the invention was owned by or under obligation of assignment to a university at the time the invention was made. There is an exception to this exception for when federal funding was required to reduce the invention to practice.
Date of enactment, applying to any patent issued on or after.
We expect the prior user defense could be valuable to defendants in software patent litigations, although the defense is available only to patents issuing after the date of enactment, and we have some concerns with how such a defense would fit within overall case strategy.
Section 6. POST-GRANT REVIEW PROCEEDINGS
Creates a European-style opposition proceeding, whereby third parties may challenge the patentability of an issued patent in an inter partes proceeding before the PTO within one year after a patent issues.
Like inter partes reexaminations, these post-grant review proceedings will have a preclusive effect on the party who brings them — i.e., that party may not assert either in a civil action or ITC action a defense of invalidity on any ground raised or that could have been raised during the post-grant review proceeding.
One-year after date of enactment, applying to any patents issued before, on, or after that date.
Based on experience with inter partes reexamination proceedings, we do not expect post-grant review to provide much help for defendants in patent litigation. Many venues do not grant stays pending reexamination, and in general the PTO is more friendly to patentees than the district courts. Nonetheless the procedure may be useful in narrow circumstances, such as when a European counterpart has already been rejected in an Opposition proceeding and a U.S. patent issues.
Section 9. VENUE
Changes venue from appeals of PTO decisions that are now filed in the District of D.C. to the Eastern District of Virginia, which is closer to the new PTO headquarters.
Date of enactment, applying to any civil action filed on or after
We generally recommend that appeals be made to the Federal Circuit when that alternative is available, and the PTO has recently taken the position that many issues that have been appealed to the D.D.C. (such as appeal of B.P.A.I. decisions in reexamination) are now subject only to appeal in the Federal Circuit.
Section 10. FEE SETTING AUTHORITY
Gives PTO fee-setting authority and control of fees subject to limited Congressional oversight. Please contact us for additional details if you would like to know more about these provisions.
Also gives universities micro-entity status and hence reduced filing fees.
Date of enactment
Along with Section 22, this was one of the most contentious sections in the bill, since the House Appropriations Committee has never given plenary authority to an Executive agency to manage its own budget. H.R. 1249 represents a political compromise, which was approved by PTO Director David Kappos and the Obama Administration
Section 14. TAX STRATEGIES DEEMED WITHIN THE PRIOR ART
Deems tax strategies “insufficient to differentiate a claimed invention from the prior art,” and not indistinguishable from other information available to the public that is relevant to a patent’s claim of originality.
Software that enables individuals to file their income tax returns is specifically excluded from this section — i.e., such software patents would not be deemed invalid merely as a result of this section
H.R. 1249 would also permit the PTO to seek advice and assistance from the Department of Treasury and the Internal Revenue Service to ensure that patents to do not infringe on the ability of others to interpret the tax law and that implementing such interpretations remains in the public domain.
Date of enactment, applying to any patent application that is pending on, or filed on or after, that date, and to any patent that is issued on or after that date
Clients should contact us if they have concerns about whether particular claims might be deemed invalid under this provision.
Section 15. BEST MODE REQUIREMENT
Removes as a defense to patent infringement the patentee’s failure to comply with the best mode requirement. (The “best mode” is currently required in patent applications to describe how an invention should be used)
Date of enactment, applying to proceedings commenced on or after that date.
Best mode defenses are rarely successful, and this Section merely codifies the practical reality that has existed for some time under Federal Circuit common law.
Section 16. Marking
Allow a manufacturer to write the word “patent” or “pat.” on a product, along with a reference to an internet website that the public can access free of charge to learn more about the specific patent.
Eliminates most liability for false marking
Date of enactment, applying to all cases, without exception, that are pending on, or commenced on or after, the date of the enactment of this Act
Gives statutory approval to a practice already common among patent owners. Puts a damper on cottage industry of qui tam litigation for false marking
Section 17. ADVICE OF COUNSEL
Codifies holding of In re Seagate Technology, LLC, 497 F. 3d 1360 (Fed. Cir. 2007), which held that failure to obtain advice of counsel may not be used to prove willful infringement.
Not clearly specified
MWE represented Seagate in the appeal that resulted in this holding. Please contact us if you'd like additional details.
Section 19. JURISDICTION AND PROCEDURAL MATTERS
Includes general prohibition against joinder of multiple defendants in a single lawsuit for infringement of the same patent by different accused products
Date of enactment, applying to any lawsuits followed on or after that date.
Could bring end to what is now a common practice by NPEs.
Section 23. SATELLITE OFFICES
Requires the Director to establish three or more satellite offices within a three-year window, subject to available resources, to carry out the responsibilities of the PTO
Section 26. PRIORITY EXAMINATION
Requires that the PTO establish regulations that prioritize examination of applications for products, processes, or technologies that are important to the national economy or national competitiveness without recovering the aggregate extra cost of providing such prioritization
Creates a “Track I” fee of $4,800 that would allow an inventor to receive a “prioritized” examination of his or her patent
The patent pledge doesn't fix every problem with patents. It won't stop patent trolls, for example; they're already pariahs. But the problem the patent pledge does fix may be more serious than the problem of patent trolls. Patent trolls are just parasites. A clumsy parasite may occasionally kill the host, but that's not its goal. Whereas companies that sue startups for patent infringement generally do it with explicit goal of keeping their product off the market.
I like the idea of introducing private solutions. I've personally worked on a few. An underlying problem is that the economics of innovation are quite different for different technologies, so even if the law applied the same way (which is doesn't; claim construction is rarely an issue in claims to chemical compounds), the balance between stronger and weaker patent rights would be different.
It's worth noting that the pledge wouldn't affect any of the litigations I currently work on, or even any litigation I have ever worked on. Patent infringement lawsuits against startups (not founded by non-former employees) are a very recent development, which can be linked to the large-scale aggregation of patents by non-practicing entities over the past ten years.
Suppose you're allocating computer memory to local variables associated with a host of objects (maybe millions). You need to free up that memory when an object is no longer needed. So you need a way to be able to tell whether the memory still has any local variables still in use pointing to it.
This can be visualized as a directed graph. The set of nodes with only outgoing edges are the variables still in use. The nodes with no incoming edges represent the memory no longer in use.
And it appears that at any given moment, the set of nodes with no incoming edges will always form a cycle -- eddies in the directed graph that represents your memory allocation.
For some reason, I find that aesthetically satisfying.