Starting with the top clock and moving anti-clockwise around the others, the hour hand moves back 1 hour, then 2, then 3 etc, while the minute hand moves forward 10 minutes each time.

Starting with the top clock and moving anti-clockwise around the others, the hour hand moves back 1 hour, then 2, then 3 etc, while the minute hand moves forward 10 minutes each time.

Start with the top left clockface, and move around the others clockwise. The minute hand moves backwards by 15 minutes, then 20, then 25 etc, while the hour hand moves forward 2 hours, then 3, then 4 etc.

Starting with the top clockface, and moving clockwise around the others, the minute hand moves forward 15 minutes, while the hour hand moves back 2 hours each time.

Start with the top left clockface, and move around the others in a clockwise direction. The sum of the numbers pointed to by the hour and minute hand follows the sequence 14, 15, 16, 17 and 18.