In the late 60s, he got involved in the Midpeninsula Free University, where he delivered classes about topics like How to end the IBM Monopoly, Computers Now and Procrastination.[5] From 1973 to 1980, he worked at Xerox PARC, where, among other things, he worked on the Gypsy word processor and Smalltalk. Copy and paste was first implemented in 1973-1976 by Tesler and Tim Mott, while they were working on Gypsy for Xerox Palo Alto Research Center.[6]