This program draws quarters repeatedly, but by changing the number of lines stitched from a single point you can change it to stitch part, half or full circles, The parameters are there to enable exploration of patterns. I've included some of the variants I find interesting.

It uses two functions:

• aLine -to stitch a line, and move back to the same point
• Quarters - to draw lines radiating from a point to create a quarter circle.

TurtleStitch makes it easy to pull code apart to explore what sections do. I tend to keep 'reset' and any variables separate from the main program, as I often copy this part and try out different values.

• Link to code on TurtleStitch website

Click on image thumbnails to see the full size.