Gianni Wise, “Turtle inversion I”, 180x150cm, 2016, lead and carbon media on Saunders Waterford 310gsm. Image courtesy the artist

Gianni Wise, “Turtle inversion II”, 180x150cm, 2016, lead and carbon media on Saunders Waterford 310gsm. Image courtesy the artist

Turtle inversion, Graphite and conté on acid-free paper, 1.8 x 1.5 m

From the original Turtle Geometry, Computer Assembly Language dot-matrix computer paper based on an early algorithm developed by Hal Abelson, a professor in the computer science department at MIT (and an activist for internet freedom). Abelson has been a founder and director of such public interest groups as Creative Commons. The Turtle, a key early code, responds to 4 basic commands (as does much of early coding and algorithms):
•FORWARD d: The turtle moves forward d steps in the direction of its current heading, and draws a line from its initial position to its final position.
•MOVE d: Same as FORWARD d without drawing a line.
•TURN a: The turtle changes it heading by rotating in the plane counterclockwise from its current heading by the angle a.
•RESIZE s: Changes the turtle step size by the factors.