Use arrow keys to move. This is a rudimentary multiplayer test which can support three players. It doesn't seem to work quite properly. Click the green flag, then the stop sign, then wait a second, then press the green flag again. Test this by opening another tab and putting this project in it.
If it isn't working, stop it, wait a second, then press the green flag. Also, it might glitch if you don't move. It was actually quite easy to make. I made it in less than 30 minutes. Updates: Oct 5: Fixed weird bug where it didn't reset.