snaparea shape-number [x y] [xsize ysize]

Copies the graphics in the defined area and pastes it in a turtle shape. [x y ] is the top, left starting point, and [xsize ysize ] determines the size of the rectangle that is copied into the shape. See snapshape.

Example:

pd rt 11 fd 5000
snaparea 1 [20 20] [60 60]
setsh 1