The first number on iPhone app in the Apple app store was a graphical entertainment app named “Koi Pond” which simulated the physics of touch water that had a koi fish swimming around in it. In January 2009, I was fortunate to speak with Bill Trost, the designer for Blimp Pilots which developed the app. The group was a bunch (five people) who formerly worked at Sony Online at EverQuest.
I was especially interested to learn that the app had been used in therapeutic ways that the app builders did not anticipate.
You hear my discussion with Bill in the 20 minute discussion I had with him.