Caterpillar automaton.
Easy to print: only the cam shaft prints with supports enabled.
Easy to assemble: requires no glue. All parts friction-fit together.

Assembly instructions

Remove the support structure from the cam shaft and smooth out areas that seem too rough.

Set the housing on the side and insert the stems through the housing slots.

Notice the tittle feet must point away from the hole in the housing.

With the housing still on its side, insert the extended end of the cam shaft through the hole, then slide it until it snaps into the support-slot at the opposite end of the housing.

Assemble the handle and press it on the end of the shaft.

While holding each stem, push the caterpillar's head, body parts and tail onto each stem while supporting it from below. Notice the caterpillar is facing away from the handle. Ensure each part is pressed down completely, but note that the head of the caterpillar will sit a bit higher than the other parts.