Building a 4 cylinder engine with all pistons moving up and down all at the same time.

[Brons2]

A ramjet or pulsejet, yes. A turbojet/turbofan/turboprop has “stages”.

Leap-X on 737MAX has single stage, IIRC.

 

[Rmay635703]

This reminds me of the v5 cylinder made from a 2 cylinder and a 3 cylinder motorcycle engine welded together

That one sounded a lot cooler though.