The 1974 manual of Pico, a graphics library for the Alto workstation developed at Xerox PARC. Callable from BCPL, it allowed to generate graphic output and handle input from a mouse or graphics tablet.

https://bitsavers.org/pdf/xerox/parc/memos/Newman_and_Sproull_-_PICO_Manual_197407.pdf

The manual mentions a planned Interlisp callable version but I found no trace of it. Maybe Pico evolved into or influenced DLISP.

https://dl.acm.org/doi/abs/10.1145/965103.807428

#retrocomputing #xerox #alto #interlisp