The event structure reads the value and, depending on its last state and current state, makes a decision. You should try to look at the logic in the different states and follow what it happening.
Example -
1> Start at low state and 10 degrees
2> Control moves to 30 degrees. Old state = low. New state = low (no change in count)
3> Control moves to 15 degrees. Old state = low. New state = low (no change in count)
4> Control moves to 100 degrees. Old state = low. New state = medium (no change in count)
4> Control moves to 330 degrees. Old state = medium. New state = high (no change in count)
5> Control moves to 20 degrees. Old state = high. New state = low (going straight from high to low means we made a positive rotation. Increase count by 1)
The limits determine the zones of the low, medium, and high states. While the values I choose to use were arbitrary, you would not want to set them too low (or high) to minimize errors. Try it yourself. Set the low limit to 2 and high limit to 358 (this would make the medium zone from 3 -> 357). If you were quick (or the mouse jumped) it might be possible to move from 356 degrees (medium zone) to 4 degrees (also medium zone). So if set improperly you could complete a rotation but not know you changed zones.
On retrospect though the best values would likely be in thirds (I.E., 120 and 240) to make the zones even? I did not do too much testing.
