The drawbot, a junkbox project inspired by Bill Paulson, is driven by a couple of $3 steppers from American Science and Surplus, some cheap H bridges and an Arduino clone. Software is free from Makelangelo.com. It does the heavy lifting math to convert from X-Y coordinates to the “inches of string” coordinates the polar geometry imposes on its steppers. In addition to accepting normal X-Y gcode, it can take a jpeg image and use the traveling salesman algorithm to generate a single path reflecting the darkness of different areas in the image as it’s doing in the picture above. Such a path is ideal for a plotter that doesn’t have pen lift capability. Yet.