Did no one else build and use a trebuchet during their school days?
It was actually very surprising just how far and accurately you could toss the projectile though the admins got upset when we wanted to toss an old Volkswagen carcass. It's was also surprising how interested in math we became. I will admit that ours had an 8m arm which makes it a bit bigger than the one in the attached video.
Edit: Also see
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