Graphic 140. What stands on a conveyor is carried by the collision code, not here: when something lands on one of graphics 140 to 143, CONVEYOR_PUSH adds to its step the pair from CONVEYOR_STEPS for that graphic, on every other turn, once a turn -- bit 3 of the conveyor's +D says it has pushed this turn. All this routine does is clear that bit, so it can push again next turn.

Measured in the simulator in room 37: standing on graphic 140 he went up two units in U every other turn, and on graphic 142 the same in V.