In 1979, Christopher Tyler of Smith-Kettlewell Institute, a student of Julesz and a visual psychophysicist, combined the theories behind single-image wallpaper stereograms and random-dot stereograms (the work of Julesz and Schilling) to create the first black-and-white "random-dot autostereogram" (also known as single-image random-dot stereogram) with the assistance of computer programmer Maureen Clarke using Apple II and BASIC.