Stone arches are all about compressive forces, the way each block pushes against its neighbours to keep the whole thing standing. Levers and gears are the opposite dance, turning tension and torque into motion. Both are the same equation just in different regimes. If you think of a stone arch as a series of tiny levers locked together, you see the balance of forces as a puzzle: every stone’s weight is countered by the next, just like each gear’s bite must match the next to keep the chain moving. So yeah, geometry explains balance, whether the arch holds a bridge or a gear keeps a machine turning.