In 1979, the computer programs were tested on a class of freshman engineering graphics
students. Application of symmetry was also used in engineering and product design.
This is a copy of a paper published in Computer Aided Design, volume 12, no. 1, January 1980.

Heech's explanation of 28 basic interlocking tiles

Computer generated Escher tiles by William Chow 1979

Product design with Solid Works