MacPaint was written by Bill Atkinson, a member of Apple's original Macintosh development team.[1] The original MacPaint consisted of 5,804 lines of Pascal computer code, augmented by another 2,738 lines of 68000 assembly language.[6] MacPaint's user interface was designed by Susan Kare, also a member of the Macintosh team.[7] Kare also beta-tested MacPaint before release.[7]