In Tangle, Inc. v. Aritzia, Inc., the Ninth Circuit reversed a Rule 12(b)(6) dismissal, holding that the selection and arrangement of otherwise unprotectable sculptural elements can be protected and that kinetic, manipulable works are sufficiently 'fixed.'
Computer Associates v. Altai adapted the idea-expression dichotomy to computer programs through its abstraction-filtration-comparison test, filtering out elements dictated by efficiency, external constraints, and the public domain.
In Nichols v. Universal Pictures, Judge Learned Hand articulated the abstractions test for separating unprotectable ideas and stock characters from protectable expression, the most enduring tool in nonliteral copyright analysis.
Baker v. Selden held that copyright in a book explaining a bookkeeping system protects the explanation, not the system itself, founding the idea-expression dichotomy later codified at 17 U.S.C. § 102(b).
