Two machines. Nothing downloaded.
Air-cooled radial aero engine
Drag to orbit · scroll to zoom · hover a part to name it · space, E and S
Both machines are built when the page loads. Dimensions become profiles, profiles get revolved or extruded, and the results are merged into the parts you can see. A cylinder barrel is one revolved sawtooth, a rail is one closed cross-section swept down the track, and a propeller blade is a stack of NACA sections lofted with twist.
Pistons come from the exact planar slider-crank. The valve gear closes a four-bar chain by intersecting circles every frame. That is why a longer rod visibly dwells at top dead centre, and why a rod length that cannot physically reach refuses to move rather than stretching.
Every machine is a small JSON object of numbers. Copy the spec, hand it to an agent, get a different machine back. Export the result as GLB and it drops straight into an avatar scene, a product page, or the glTF viewer.