[warrenn]

Sorry, I was planning to learn German (for a long visit) but didn't get very far.

Clicking and dragging on the ends of the arc does allow one to change its angle. This allows one to make an arc whose angle is 90 degrees (quarter circle) or 180 degrees (half circle).

Clicking or dragging on one of the 6 resize squares on the arc allows you to rotate it (with the command key down).

The canvas is the drawing region - the part of the window you use for drawing.

Hope this helps.

Warren Nagourney