Rectangle Bin Packer
Repeatedly tap the buttons at the bottom of the screen to view the packing algorithms in action. Rectangles are numbered as they are added, and flipped rectangles are marked with "F". You can also tap the test button to run a battery of tests.
Get the full source code here: https://github.com/Tw1ddle/Rectangle-Bin-Packing-Demo
I'm on Twitter: https://twitter.com/Sam_Twidale