This explains something, I think! Luca Cardelli and Mark Manasse later worked at the Digital Systems Research Center in Palo Alto, which was formed in 1984 after PARC fired Bob Taylor. Mark helped write the window system we used, and at some point a cat appeared, which would sleep until you moved the mouse and then come over to pat at the mouse. My impression was that Luca wrote it, be he was cagy about it. This later evolved into xneko for X Windows. -Larry