The Supreme Court’s abstract ideas exception to categorical subject-matter eligibility under 35 U.S.C. § 101 has become the bane of computer-implemented inventions. In June of 2014, the Supreme Court, in Alice Corp. Pty. Ltd. v. CLS Bank International, affirmed the framework for patent-eligibility initially set out in Mayo Collaborative Services v. Prometheus Laboratories, which includes the following two steps:
Step 1: Determine whether the claim is directed to an abstract idea
Step 2: Examine the elements of the claim to determine whether it contains an “inventive concept” sufficient to “transform” the claimed abstract idea into a patent-eligible application.
Despite the Alice Court’s clarification of the proper test for patent eligibility, it remains exceedingly difficult to determine whether a particular computer-implemented invention will ultimately be deemed patent eligible. The Alice decision has led to dramatic changes in how 101 issues are resolved by lower courts and the USPTO. For example, observers have witnessed an alarming increase in the invalidation rate of patents on computer-implemented inventions. Overcoming 101 rejections at the Patent Office has become unprecedentedly difficult, with some art units rejecting over 80% of all patent applications under 101, and some even retracting previously allowed claims.
Given the abysmal survival rate of computer-implemented inventions, many have speculated that software patents are dead. Such a dire prognostication is supported by some rather straightforward syllogistic reasoning. Software is algorithmic. Algorithms have commonly been labeled as abstract ideas. Abstract ideas are unpatentable. Therefore, software is unpatentable.
 Before the Supreme Court’s decision in Bilski v. Kappos, 130 S.Ct. 3218 (2012), the Federal Circuit’s easily applied machine-or-transformation test was dispositive of eligibility. However, the Bilski court indicated that the machine-or-transformation test was not the “sole test” and that it provided only a “useful and important clue” to eligibility. Id. at 3258.
 See, e.g., Robert Sachs, Fenwick & West’s Bilski Blog, Tracking #AliceStorm: The Dead Keep Piling Up (Apr. 10, 2015), available at http://www.bilskiblog.com/blog/2015/04/alicestorm-update.html (noting a combined 70.5% invalidation rate by the district courts and the Federal Circuit)
 See, e.g., Kate Gaudry, IPWatchdog.com, Post-Alice, Allowances are a Rare Sighting in Business-Method Art Units (Dec. 16, 2014), available at http://www.ipwatchdog.com/2014/12/16/post-alice-allowances-rare-in-business-method/id=52675/
 In the broadest sense, an algorithm is an ordered sequence of steps for accomplishing a defined goal. An algorithm is more or less a process.
However, a lack of abstractness is not the sine qua non of patent eligibility. Rather than excluding abstract ideas in an epistemological sense, the Supreme Court has emphasized that preemption is the chief concern underlying its exclusion of abstract ideas from patent eligible subject matter. According to the Court’s rationale, granting a limited monopoly on an abstract idea is dangerous because an abstract idea represents a building block of human ingenuity. Tying up building blocks with patents might impede progress rather than foster it, thus contravening the policy behind the patent system, which is to promote development of the technical arts.
As is evident from Step Two of the Mayo framework, a claim directed to an abstract idea is patentable if it has been inventively applied to a particular problem.
So what constitutes an inventive application of an abstract idea? Alice left open the possibility that improvements to the functioning of the computer itself or improvements to another technology or technical field might be eligible for patenting. Unfortunately, useful examples of meaningful limitations to delimit such improvements have been hard to come by. The Court’s precedents have only identified what is not considered meaningful: functional or generic computer hardware, insignificant post-solution activity, and arbitrary field-of-use limitations.
Positive examples of patent eligibility are rare and case-specific. As of the writing of this article, less than twenty district court opinions have maintained the patent-eligibility of computer-implemented inventions. Unfortunately, scouring patent-eligible claims for meaningful limitations is of limited use. Meaningfulness cannot be easily divorced from the context of the claimed solution and the problem being solved. In other words, what is meaningful for one invention is not necessarily meaningful for another. Thus, it is hard to imagine how copying the meaningful limitations from the latest patent-eligible case could confer eligibility. Even if it were so easy, such a technique would quickly become widespread enough that it would transform what was once considered unconventional into a conventional and meaningless drafting effort. And the Court has already made clear that patent eligibility cannot be conferred by mere drafting effort.
 Alice, 134 S.Ct. at 2358 (“Thus, if a patent’s recitation of a computer amounts to a mere instruction to implement an abstract idea on a computer, that addition cannot impart patent eligibility. This conclusion accords with the pre-emption concern that undergirds our §101 jurisprudence.”) (quotations and internal citations omitted).
 Steven Callahan, Northern District of Texas Blog, Alice: The Death of Software-Related Patents? (May 1, 2015), available at http://www.ndtexblog.com/?p=3550&utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+NDTexBlog+%28Northern+District+of+Texas+Blog%29
 Alice, 134 S.Ct. at 2358 (“A claim that recites an abstract idea must include ‘additional features’ to ensure ‘that the [claim] is more than a drafting effort designed to monopolize the [abstract idea].’”)
So if meaningful limitations cannot be copied or learned, how can they be identified? Supreme Court and Federal Circuit precedent offers a few clues. Post-Alice, only one Supreme Court case and one Federal Circuit case have identified patent-eligible computer-implemented inventions: Diamond v. Diehr, 450 U.S. 175 (1981), and DDR Holdings, LLC v. Hotels.com, L.P., 773 F.3d 1256 (Fed. Cir. 2014).
Both Diehr and DDR Holdings featured technological solutions to concrete, real-world problems. For example, in Diamond v. Diehr, a computer implementation of the Arrhenius equation was used to precisely control the opening and closing of a rubber molding press in response to continuous temperature and pressure readings taken from inside the press. The mere presence in the examined claims of a mathematical formula did not destroy patent eligibility because the formula was applied using a particular machine in order to improve a rubber curing process. The integration of the abstract idea with a rubber molding press avoided preempting all uses of the Arrhenius equation outside of rubber curing, and the integrating steps were included as claim limitations.
DDR Holdings provides an example of an inventive concept that did not incorporate other hardware. In DDR Holdings, the Federal Circuit found eligible an e-commerce system that helped to retain visitor traffic by displaying third-party product information from within a generated web page that gave the viewer of the page the impression that she is viewing pages served by the host website. The claims in DDR Holdings were said to “stand apart because they do not merely recite the performance of some business practice known from the pre-Internet world along with the requirement to perform it on the Internet. Instead, the claimed solution is necessarily rooted in computer technology in order to overcome a problem specifically arising in the realm of computer networks.” DDR Holdings, 773 F.3d at 1257. The court distinguished the claims in DDR Holdings from those found ineligible in a previous case on the grounds that the claims “do not broadly and generically claim ‘use of the Internet’ to perform an abstract business practice (with insignificant added activity).” Id. at 1258. Unlike the claims in the previous case, the claims in DDR Holdings “specify how interactions with the Internet are manipulated to yield a desired result—a result that overrides the routine and conventional sequence of events ordinarily triggered by the click of a hyperlink.” Id.
Yet, at first blush, DDR Holdings seems difficult to reconcile with the Supreme Court’s holding in Gottschalk v. Benson, 409 U.S. 63 (1972). In Benson, the Supreme Court found ineligible for patent a computer-implemented method on an algorithm for converting binary-coded decimal into pure binary. The algorithm was useful for solving a problem that arose only in the realm of digital computers, namely how a number is represented digitally. The reviewed claims in Benson even specified how interactions with a reentrant shift register were manipulated to convert signals from BCD to binary.
 Claim 8. The method of converting signals from binary coded decimal form into binary which comprises the steps of
(1) storing the binary coded decimal signals in a reentrant shift register,
Nevertheless, Benson is distinguishable. Although the claims under review in Benson featured specific and well-defined limitations, the examined claims merely recited the steps of the algorithm itself, which the Court described as having “no substantial practical application except in connection with a digital computer.” Benson, 409 U.S. at 71. In other words, the algorithm was not being applied to solve a concrete, real-world problem. This accords with the Supreme Court’s later characterizations of Benson. For example, the Alice Court provided the following justification for holding the BCD converter ineligible:
Because the algorithm was an abstract idea, the claim had to supply a “new and useful” application of the idea in order to be patent eligible. But the computer implementation did not supply the necessary inventive concept; the process could be “carried out in existing computers long in use.” We accordingly “held that simply implementing a mathematical principle on a physical machine, namely a computer, [i]s not a patentable application of that principle.”
Alice, 2357-58 (citations omitted).
Parker v. Flook, 437 U.S. 584 (1978), is likewise instructive. In Flook, the claimed invention was directed to a mathematical formula for updating alarm limits in a catalytic conversion process. However, the Court determined that an “alarm limit” was nothing more than a number. Thus, calculating a number that might have some real-world use is not sufficient if the inventive application does not effectively limit the invention. In contrast, in Diehr, the outputs of the Arrhenius equation were used to control a separate machine, but the incorporation of the machine limited the use of the equation so as to avoid preemption of the underlying abstract idea. Alarm limits, which seemed to represent nothing more than the numeric outputs of a mathematical equation, did not meaningfully limit the use of the equation to a particular application. Thus, Flook stands for the proposition that insignificant post-solution activity will not confer patent eligibility.
In sum, a patent-eligible invention should comprise a technological solution to a concrete problem. See, e.g., Diehr; see also DDR Holdings; but see Benson (finding ineligible a computer-implemented algorithm for converting binary coded decimal, which represented a technological solution to an abstract problem). However, the claimed features making up the technological solution (inventive concept) must restrict the invention to a particular application or field of
(2) shifting the signals to the right by at least three places, until there is a binary ‘1’ in the second position of said register
(3) masking out said binary ‘1’ in said second position of said register,
(4) adding a binary ‘1’ to the first position of said register,
(5) shifting the signals to the left by two positions,
(6) adding a ‘1’ to said first position, and
(7) shifting the signals to the right by at least three positions in preparation for a succeeding binary ‘1’ in the second position of said register.
use. Compare Diehr (Arrhenius equation integrated with rubber molding press, effectively limiting it to a particular industrial use), with Flook (mathematical equation used to calculate alarm limits). Conventional computer components fail this last requirement because they do not limit the scope of the invention to its application. See Mayo and Alice.
But what help is identifying technological solution? Technological solutions to concrete problems are more likely to represent inventive applications of an abstract idea. Applying an abstract idea to solve a particular problem requires more effort and ingenuity than merely reciting an abstract idea along with the instruction that it should be applied to a particular field or implemented using a generic computer. If patentees are required to describe how the abstract idea has been applied to solve a particular problem, it belies a certain level of development of the idea beyond mere speculation that such an idea could be made to work in general. The more a solution must be developed (i.e., enough to delimit how the idea has been applied as opposed to merely identified), the more specific and defined the invention is likely to be. On the other hand, highly functional or generic claims are more likely inadvertently preempt or discourage others from using an abstract idea because the boundaries of the so-called inventive concept are hard to discern.
As a practical matter, when drafting or amending claims, it may be helpful to explore how the business or industrial problem (i.e., a concrete, real-world problem) identified by the application was solved by the claimed invention. For existing claims that are written very broadly, it may be necessary to reexamine the invention at a deeper level. In terms of claim drafting strategy, high-level descriptions of the technological solution in very general and abstract terms should be avoided. If the claim recites limitations that read like a list of marketing features from a product brochure, the claim is likely too broad and may be difficult to repair in such a form. Instead of drafting a claim to cover what the invention does (i.e., a functional description), draft a claim that focuses on how the claimed invention works. Such a format will make it easier to identify or add limitations that are addressed to the inventive concept (i.e., the application of the abstract idea to the particular problem at hand).
Assuming the inventors have actually reduced the invention to practice, it may be useful to explore what technological hurdles had to be overcome in order to make the invention work. Such hurdles or sub-problems may offer useful clues that help in identifying meaningful limitations or essential technical features of the claimed invention that might not otherwise be understood or appreciated at a higher level of abstraction. If another skilled person were to attempt to solve the same problem and would have to incorporate a similar technological solution, it may be easier to draft an eligible claim on the particular essential technical feature than on a generic description of the system as a whole. Such solutions are more likely to distinguish the claimed solution from others, thus making it unconventional.
 Mayo made clear that transformation into a patent-eligible application requires “more than simply stat[ing] the [abstract idea] while adding the words ‘apply it.’” Mayo, 132 S. Ct. at 1289.