mower sometimes requires result
mowing is maintenance. riding_mower is not lawn_mower. riding_mower is internal_combustion_powered_device. power_mower is not lawn_mower. riding_mower is not internal_combustion_powered_device. push_mower is not lawnmower. riding_mower is not power_mower. riding_mower is power_mower. power_mower is lawn_mower. riding_mower is lawn_mower.