Used by the routine at ADJ_DZ_FOR_OBJ_INTERSECT.

Called by ADJ_DZ_FOR_OBJ_INTERSECT when the object met in Z is one of graphics 140-143. These four share the plain block's sprite but move what meets them, in practice what stands on them: on every other turn (bit 0 of TURNS set) the mover's step gets two units in the direction the graphic's low two bits pick from the table at CONVEYOR_STEPS -- 140 +U, 141 -U, 142 +V, 143 -V. Only the first mover in a turn is pushed: bit 3 of the block's +$0D, set by ADJ_DZ_FOR_OBJ_INTERSECT just after this, is cleared only by the block's own update routine (CONVEYOR_PLUS_U and its three neighbours).

None of this ran in the build's sessions. It was run in the simulator instead: the player's legs falling onto each of the four graphics were given +2 U, -2 U, +2 V and -2 V on an odd turn, nothing on an even one, and nothing with the block's bit 3 already set.