These drawings are from an exercise found in Chapter 6 of Drawing on the Right Side of the Brain (4th ed.) by Betty Edwards. Essentially, you “copy” or “trace” your non-dominant hand (which is holding the plastic picture plane) using a dry-erasable marker. You are to include the major lines in your hand, including wrinkles.

The lines are fairly sloppy because the marker actually didn’t work that well on the plastic, and there’s a grey shadowy line along the drawn line, due to the overhead light being on when I took the photos of the drawings (which are now wiped clean off the plastic picture plane).

After a number of practice drawings, the next step of this exercise is to use the picture plane drawing as a model while you draw the pose on paper.