Microsoft toggle video predates Apple’s slide-to-unlock patent

April 6, 2014, 1:41 PM UTC

FORTUNE — AppleInsider‘s Daniel Eran Dilger and FOSS Patents‘ Florian Mueller have locked horns in a fierce debate over whether Samsung ought to be held liable for copying Apple’s (AAPL) slide-to-unlock patent — one of five patents at issue in the $2 billion infringement trial that began last week.

Dilger posted his piece on Saturday:

Apple unlocks new Copy Cat docs as evidence Samsung pilfered iPhone unlock

Mueller responded the next day:

‘Teaching away’ is why Apple’s rubber-banding patent has far more merit than slide-to-unlock

Dilger’s strongest evidence are internal documents that show Samsung researchers working hard to match the intuitiveness of the “unlock” mechanism that Steve Jobs demonstrated — to appreciative applause — at the 2007 unveiling of the first iPhone.

Mueller’s strongest evidence is the attached 1991 video, in which the University of Maryland’s Catherine Plaisant — then employed by Microsoft (MSFT) — demonstrates a variety of touchscreen toggle switches, including (at the 2:55 mark) a slider.

Does the existence of this video invalidate Apple’s case? That, I suppose, is for the jury to decide.