25mm glass marbles are used as balls. Every minute a trigering device will actuate a motor which liftsup and drops one ball at the minute tray. When the minute is tray ( 5 mins) is filled the tray trips over with one carry over ball moving to the next tray and the remaining balls returning to the sump. When the 5 Mins tray is filled ( 60 Mins) it trips and one carry over ball move to next Hour tray. When the Hour tray is filled (12 Hrs) it trips with all the balls moving to sump except one ball which is fixed to the tray. This happens at 1 'O' Clock and it is a spectaculor movement with all the balls moving to the sump.