Because of another project (coming soon), I had a surplus of assorted buttons around the house. When I had an entire Saturday morning to kill and four kids and a Moo and Pa to amuse, I found this project. It was so fun and easy! I had everything we needed around the house: clothespins, buttons, straws, twist ties, and a bit of masking tape.
First we found four same-size buttons.
Next, we put the first button on a twist tie (in one hole, down through the other and twisted it to keep the button on tight). Then we put a piece of straw on (about and inch and a half). Then the next button and threaded the twist tie back through the other hole to keep the button on and twisted that one tight.
We did that a second time with two more buttons, a straw piece, and a twist tie. Then we put one of these wheels and axles through the hole in the clothespin and the other up by the spring and secured that with a bit of tape around the clothespin.