A custom implementation of UIScrollView pagination which allows only up or down movements (never diagonal)
Have you ever tried to do an UIScrollView with horizontal and vertical pagination? No? Try to create one and set these to true:
[scrollView setPagingEnabled:YES];
[scrollView setDirectionalLockEnabled:YES];
Did you notice how it allows diagonal pagination? Unfortunatelly (to my knowledge) there is no easy way to solve this. So I just implemented everything from scratch!