The U.S. Court of Appeals for the Federal Circuit is increasingly using the “plainly dissimilar” formulation to affirm summary judgment of noninfringement in design patent cases. What began simply as a narrow comment in Egyptian Goddess Inc. v. Swisa Inc., decided by the Federal Circuit in 2008, about what obvious noninfringement cases might look like now appears to be doing much heavier work — allowing courts to resolve infringement disputes by focusing on identified differences without engaging the ordinary-observer inquiry that has long governed design patent law.
If “plainly dissimilar” is now functioning as a practical substitute for the ordinary-observer test, then design patent doctrine may be inching toward a difference-centered regime that gives accused infringers a meaningful procedural advantage.
Recently, this shift came to a head in Range of Motion Products LLC v. Armaid Co. in February. There, the Federal Circuit affirmed summary judgment of noninfringement in a case involving body-massaging devices that shared curved clamshell arms, a hinge structure with adjustment slots, and handles. The majority applied the plainly dissimilar framework. U.S. Circuit Judge Kimberly Ann Moore dissented. Her dissent framed the issue not simply as a disagreement over a close case, but as a challenge to the structure of the inquiry itself: whether Egyptian Goddess has inadvertently shifted the question of infringement away from the one the U.S. Supreme Court in Gorham Co. v. White in 1871 said controls (would an ordinary observer be deceived?) to one it does not (are these designs plainly dissimilar?).
The extent of the drift comes into focus when the Federal Circuit’s decision in Range of Motion is set against one of its older ones. In Litton Systems Inc. v. Whirlpool Corp. in 1984, the court stated that “minor differences between a patented design and an accused article’s design cannot, and shall not, prevent a finding of infringement.” That proposition follows naturally from the ordinary-observer test in Gorham: if infringement turns on overall visual impression, small variations in detail should not necessarily defeat what is otherwise a compelling visual match. As the Court explained in Gorham, if “mere differences” were the test, there never could be piracy of a patented design, for human ingenuity has never yet produced a design exactly like another.
From “Ordinary Observer” to “Plainly Dissimilar”
Design patent infringement has long been governed by the ordinary-observer test. Under Gorham, the question is whether, in the eye of an ordinary observer familiar with the prior art, two designs are substantially the same such that one might be purchased for the other. In Egyptian Goddess, the Federal Circuit reaffirmed that rule but also made the observation that, in some cases, the claimed and accused designs will be sufficiently distinct, such that it will be clear “without more” that the patentee has failed to meet its burden. Importantly, the court in Egyptian Goddess conducted a three-way comparison of the patented design, the accused design, and the prior art before affirming summary judgment of noninfringement. Taken in context, the “plainly dissimilar” language would seem to be best understood as nothing more than a description of what obvious cases might look like — certainly not a distinct test or express instruction to bypass the ordinary-observer analysis in closer ones.
Despite this, Egyptian Goddess created an opening for a shift in the law. In Ethicon Endo-Surgery Inc. v. Covidien Inc. in 2015, the Federal Circuit affirmed summary judgment of noninfringement by conducting its own de novo visual comparison between the accused device and the design, concluding that residual ornamental features were plainly dissimilar. Not only did the Ethicon court employ the plainly dissimilar formulation, it leaned on Egyptian Goddess for the additional proposition that comparing the claimed and accused designs with the prior art was unnecessary when noninfringement appeared obvious — even though the court in Egyptian Goddess did just that. In the same month, High Point Design LLC v. Buyers Direct Inc. applied the same test and affirmed noninfringement without a prior art comparison.
In Super-Sparkly Safety Stuff LLC v. Skyline USA Inc. in 2020, the Federal Circuit did the same, but in a case that actually appears to have been more obvious: the claimed design featured rhinestones on both the cylinder and the bottom of a pepper spray canister, while the accused product had rhinestones only on the cylinder. In 2025, however, the same framework began to be applied to less-clear cases. In North Star Technology International Ltd. v. Latham Pool Products Ltd., the Federal Circuit affirmed summary judgment in a four-page opinion, emphasizing that the patented pool design featured straight edges and angular geometry while the accused product had a curved, rounded appearance. The designs nonetheless shared a common product category — rectangular pools with tanning ledges, step configurations, and comparable proportions. The court did not explain at length why those shared features were insufficient to create a genuine dispute of material fact. North Star later sought rehearing en banc, which the court denied.
Range of Motion now appears to have solidified the doctrinal shift. The majority affirmed by treating the governing framework as allowing summary judgment where, after accounting for functionality and focusing on the protected ornamental aspects of the design, the accused and claimed designs are sufficiently distinct as a matter of law. In the majority’s view, even if the products shared a similar general concept, that was not enough to create a triable issue once the legally relevant ornamental comparison was made.
Judge Moore’s dissent was not just a disagreement about the outcome of a close case. It was a challenge to the structure of the inquiry itself. Her main point was that Egyptian Goddess may have actually shifted the central question. The dissent also pointed to empirical support: an amicus brief in North Star presented survey data in which ordinary observers were shown design pairs from cases where infringement had been found and asked whether those designs were plainly dissimilar. More than 60% said yes. The majority did not engage with that data. Judge Moore also identified North Star and Ethicon as cases where she could not rule out that the framing shift was outcome-determinative.
Range of Motion may prove to be the most important recent decision in the Federal Circuit’s evolving use of the plainly dissimilar formulation, because it suggests that the concept is no longer confined to screening out only the easiest noninfringement cases. Unlike the court’s 2015 decisions in Ethicon and High Point, Range of Motion — particularly when read alongside North Star — applies the same framework in a case where the designs shared not just a product category but a common design concept and several prominent visual features. That makes it significant not merely as another application of existing precedent, but as a sign that “plainly dissimilar” has evolved from a narrow description of obvious cases into a powerful summary judgment tool capable of resolving disputes that once might have been expected to proceed under the ordinary-observer analysis.
Importantly, the two formulations are not interchangeable. As Judge Moore pointed out, the ordinary-observer inquiry asks whether similarities are strong enough to create a risk of confusion — it centers on what the designs share. The plainly dissimilar inquiry asks whether differences are pronounced enough to foreclose liability — it centers on what sets them apart. In any case where designs share a basic concept but diverge in execution, the answer can depend entirely on which question is asked.
A Path Forward
To be sure, the Federal Circuit’s recent approach has a plausible institutional justification. Courts may worry that an undisciplined emphasis on overall similarity could allow design patent owners to claim more than their designs show — a concern that is especially acute in crowded product markets where many products share broad shapes or common arrangements. Paying close attention to differences could serve as a real gatekeeping function. But that does not answer the harder question: how much is an analysis of the differences between a patented design and an accused product compatible with an ordinary-observer framework at summary judgment? If identified differences alone are enough to render designs plainly dissimilar as a matter of law, summary judgment can begin to function less as a procedural backstop and more as a merits filter that privileges a difference-centered mode of analysis.
If the Federal Circuit takes up the issue again, the necessary clarification need not be complicated. First, the court should make clear that “plainly dissimilar” is not a freestanding alternative to the ordinary-observer test, but only shorthand for the conclusion that the comparison is so one-sided that no reasonable juror could find for the patentee — cases like Super-Sparkly Safety Stuff, not cases like Range of Motion or North Star. Second, it should emphasize that identified differences must be evaluated in light of overall visual impression, rather than treated as independently dispositive. Third, it should reaffirm the requirement of comparing the claimed and accused designs to the prior art even in what might appear to be obvious cases.
The practical stakes are straightforward. For patent owners, a design patent case may now be won or lost at the level of framing long before trial. For accused infringers, the recent cases suggest that summary judgment can be a powerful tool even where a side-by-side comparison initially appears unfavorable. The law on the books still says design patent infringement turns on the ordinary observer. But the law in operation may be moving toward something narrower, more court-centered, and more dependent on whether a judge sees the dispute as a matter of overall impression or as an exercise in careful differentiation.
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