This assignment has five keys: #1, 5, 8, 11, and 15. There are eight inbetweens for this assignment.
You are to draw the 8 inbetweens according to the timing charts provided.
Here's another cool hand and arm assignment that involves a bunch of overlapping action.
The action is of a hand lifting up and then slapping down hard on a surface.
Once again, use your own arm and hand as a model for this animation. Throughout the whole action, think: "seaweed" as the primary principle. Elbow goes up first while the finger tips remain on the surface (key 5). Then the wrist comes up as the elbow drops slightly (key 8), then the arm drops suddenly, followed by the wrist and the finger tips trail (key 11). And finally, the hand slaps the surface (key 13).
Begin with inbetween #4. If you want to, go through and do all the main half inbetweens: 4, 6, and 10. Then you can stack flip the drawings to see how the action looks. This can give you an opportunity to go back and fix up anything that might look weird. If you complete 4 then do #3 but later realize you did something wrong with 4, it automatically means that 3 is wrong as well. you can't just go back and redo 4 and leave 3 as it was. Anything you did to 4 will alter what #3 should look like.
Inbetween 9 and 12 are favors. #9 is the one to be especially mindful of aswhen the elbow drops, you'll probably want to take the wrist and hand back and up further, then rotate it so that the palm is showing on 10 but have it lower than 9.
12 will be the favor to 13 which means that the heel of the hand will hit first with the fingers still up in the air, trailing just a bit.
Here's the pencil test of all the drawings as inbetweened above, shot on twos (except for the favor inbetween at the end which is on ones).
See my inbetweens