 Between 1959 and 1962, classmates Elwyn Berlekamp, Alan Kotok, Michael Lieberman, Charles Niessen and Robert A. Wagner wrote the program while students of John McCarthy at the Massachusetts Institute of Technology.Building on Alex Bernstein's landmark 1957 program created at IBM and on IBM 704 routines by McCarthy and Paul W. Abrahams, they added alpha-beta pruning to minmax at McCarthy's suggestion to improve the plausible move generator.They wrote in Fortran and FAP on scavenged computer time.