I was going to use a quadratic. Going into NYS common core geometry this year, so I've just completed algebra 1. I can easily pull a quadratic function for x values using my graphing calculator, but I don't know how to do this with screen size as a variable. I just positioned the boxes by ear in a pyui, then took their frames and put them into the code.
A quadratic is preferable over a sine, because a sine goes up and down multiple times. Quadratics look like this:
Here x would be ImageView index, and y would be the distance from the previous box. Distances are greatest in the middle, boxes are closer together towards the edges.
What I'll probably end up doing is defining x as a percentage, which represents x value over total screen width. Then on my iPad, the value is x percent of 1024.