Processing on iOS. Just stumbled upon it. What it says - processing.js in a spartan but usable mini-IDE. Nice for in between. And somehow fits well with the tablet. Ending sketches is a bit awkward, you have to tap or press on a bar at the top or something, which nobody tells you. But otherwise everything is clear. There are two more that I found, one costs 89 cents and delivers an interface analogous to PDE and the other is pr0c0d1n6 - it's quite expensive at forty-five, but it has a really usable IDE.