App icons all in one space

[StokeLee]

I turned the iPad on and off, and it reset them, but what did I do to make the icons do this? In the first pic I was attempting to move the icons, hence why they are wonky

 

[Feed Me]

I had this glitch on one of the 5.1 betas... Good to see it has lived on to the final release.

I did it by opening a folder, attempting to move the icons, and simultaneously rotating the device to landscape. Or at least something like that. I can't really remember.