Created in Gemini with the following prompt:

"create an HTML/Javascript program to simulate the the intake, compression, ignition and exhaust cycles of an internal combusition engine. The program should allow the user to control the speed of the simulation with a slider control and make use of colorful and perhaps cartoon like graphics."

There were about 4 follow up corrections to fix timing and visual issues with the simulation.  The spark was going off at bottom of intake cycle rather than at top dead center of compression and the simulation was artificially extending the piston rod to move the cylinder head to the top of the cylinder.

Still pretty impressive.  Its 519 lines of code and even with iterative corrections was completed in under 20 minutes.  I don't think many, perhaps any, human programmers could compete with that.