I decided to go home and get my toolbelt to fix it. I decided that probably tape and cardboard would be the best materials because metal and wood and stuff wouldn't really keep the right shape.
First I started by putting the tape all around the crack so that the crack would hold together.
Then I cut a toilet paper tube in half and I used the tape to tape it into place. Then I added more tape so that the whole toilet paper tube was covered. That way it would be pretty waterproof.
Then I decided to try and test it. With a little help from my little sister Nora, who is one, I tested it out. I put her in the car and pushed her around, and the wheel held!
Then a few days later when I came back to the park the wheel that I had just patched, the whole wheel, had fallen off the car. And I couldn't find the wheel. I guessed that someone had probably thrown it out. But then, the next day, when I came back, the wheel was back on the car. And the patches were still there!