Ummmm. In 2007, near a certain defense contractor, we demonstrated a 319'-wire trebuchet mounted horizontally but slight vertical a-skewed for distance/aiming.

Used a gnarly large helical gear but with integral diminishing ratio.

Gravity-powered in same way but with a 20-meter-ish tower. (Cheaper than a standard 800'-tall trebuchet.)

At release time, achieved 10 G-force (payload goal), it's velocity speed was audibly a speed of sound (arguably higher, math says Mach 2.7).

That was our lunchtime project, all started from several stage bets, a napkin diagram, and different loser(s) pay for weekly food deliveries.

Even demonstrated to some brass from an unrelated project.

Fun-time.

Oh, yes, lest I forget, bunker-required for safety (where exactly would you stand?).