This is an internal combustion engine simulator. This is based on a 4-stroke engine. The recommended speed is 60-80. The piston doesn't sync so good, for example, the exhaust may go out with the valve closed. The project may (or may not) work better in turbo mode.
When the gas is over the piston becomes slower, until it stops.
TurboWarp is a Scratch mod that compiles projects to JavaScript to make them run really fast. Try it out by inputting a project ID or URL above or choosing a featured project below.