Place 4 integers on a circle. Proceed in iterations. At every step, compute all differences of pairs of consecutive numbers. Place the absolute values of these differences between the corresponding numbers and remove the numbers themselves. Show that after performing the step several times all the numbers will become 0.
For what numbers - other than 4 - the same holds true?
Numbers on the circle can be set either randomly or by modifying each of the circled entries. To modify a number, click a little to the right or left of its centerline.
