Initialised by the routine at 34762; incremented on each pass through the main loop by the routine at 35245 (which moves the game clock forward by a minute when the counter reaches 0); reset to zero by the routine at 38276 when Willy sticks his head down the toilet; and used by the routines at 37841 (to cycle the colours of the items in the room), 38196 (to determine Maria's animation frame in Master Bedroom) and 38298 (to determine the animation frame for the toilet in The Bathroom).