countdown 1 (30 ticks at 4 seconds per tick):

countdown 2 (10 ticks at 1 second per tick):

countdown 3 (10 ticks at 10 second per tick):

countdown 4 (30 ticks at 1 second per tick):

countdown 5 (15 ticks at 2 seconds per tick):

countdown 6 (27 ticks at 3 second per tick):

countdown 7 (14 ticks at 2 seconds per tick):

countdown 7, 8 (10 ticks at 1 second per tick):

countdown 9 (5 ticks at 1 s/t) with callback "alert('callback')":