To use gravity, you only have two options: 1. Knock things down that are already high up and hope they break at the bottom. Or, 2. Haul things up and then kno

To use gravity, you only have two options: 1. Knock things down that are already high up and hope they break at the bottom. Or, 2. Haul things up and then knock them down. #1 only works in an extremely limited number of cases and gets exhausted quickly. #2 spends more energy hauling up than it gains.