Logo Turtle Graphics for the Lisp Machine

Abstract

This paper is a manual for an implementation of Logo graphics primitives in Lisp on the MIT Lisp Machine. The graphics system provides: Simple line drawing and erasing using "turtle geometry" Flexible relative and absolute coordinate systems, scaling Floating point coordinates Drawing points, circles, boxes, text Automatically filling closed curves with patterns Saving and restoring pictures rapidly as arrays of points Drawing on color displays, creating new colors Three dimensional perspective drawing, two-color stereo display