There are some great stories from legendary program Giles Goddard (Star Fox, 1080 Snowboarding) in this piece.

He remembers one time that he blew up a power supply in a new development PC, because he plugged it in at the wrong voltage. And Miyamoto noticed. "And Miyamoto got really angry and said, 'You need to go and apologise to blah-blah-blah now.'" But Goddard had other ideas.

Quick as a flash, he went to his desk and swapped the fried power supply for his computer's, and then - as if making a sudden, surprise discovery - announced, "Actually no it's fine - it's not broken." And it worked: Miyamoto was calmed. "But I did actually break it," Goddard tells me. "I just fixed it before he found out."

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The SGI Indy had a bonus feature Goddard was excited about too: a webcam. I know that doesn't sound exciting now, but back then, webcams were new, so Goddard started experimenting with it. He put ping pong balls on his face, because the camera picked them up well, and ended up creating a mo-capped facial animation prototype. He was impressed. Miyamoto was impressed. So much so, Miyamoto announced, "Well let's try and get a Mario face into that."

So, Nintendo did. Yoshiaki Koizumi took the prototype and added "bones and everything" for Goddard to use. "Then I just skinned all the polygons together - skinning was a new thing as well - and I got it all spongy, and then we just iterated on that to see what was fun." And that's how the famous N64 Mario face - the one you can pull around at the beginning of Mario 64 - came to be.