Comment by Lammy

> His answer could be most readily found in Thresh’s Quake Bible, which describes the WASD formation as an “inverted T.”

This is IBM terminology. “Inverted T” was the name for the arrow key arrangement on ThinkPads (1992) later adopted by the Apple world after the IBM-designed Powerbook 2400c (1997) made their layout the new standard for all subsequent Powerbooks/iBooks/Macbooks.

It wouldn't surprise me if the term dates all the way back to 1984 with the Model M keyboard, but I can't find any reference for that (checked Bitsavers etc) besides You Can Tell By The Way It Is versus the earlier arrow-less Model F keyboard.