IIRC, Xerox were paid in exchange for engineer visits on the understanding that Apple would produce some form of GUI. Xerox were sufficiently aggrieved with the

IIRC, Xerox were paid in exchange for engineer visits on the understanding that Apple would produce some form of GUI. Xerox were sufficiently aggrieved with the result to file a lawsuit against Apple, who were trying to do the same thing to Microsoft at the time. I don't think the Xerox/Apple arrangement is as straightforward as many make out.