Back in 2010 the 37Signals blog posted about a John Scully interview where Scully talked about Steve Jobs and his inspirations on product creation:
Dr Land was saying: “I could see what the Polaroid camera should be. It was just as real to me as if it was sitting in front of me before I had ever built one.”
And Steve said: “Yeah, that’s exactly the way I saw the Macintosh.”
The Scully interview transcript is on Cult of Mac here.