I have been waiting since 2003 for someone to release something like TrippingFest. The idea behind TrippingFest is to draw many different things with many different colors. I am tired of waiting, so I built it for the iPhone.
I have drawn quite a few pictures already: View Image Gallery
Although I do not like substituting text with icons, iPhone users are used to this. Here is a diagram for things without proper labels.
Around 2003, I wrote a drawing program with Visual Basic 5 (not 6). You could draw lots of different patterns with random colors. It had automated random drawing and around 20 different patterns. I was in middle school at the time, so it also made fart noises.
After waiting for someone to make something superior and more complete (and release it for free), I could find no programs that captured the essence of TrippingFest. In early 2009, I embarked on efforts to make a multi-platform drawing platform based on the Visual Basic program with intent to release. I chose Java and before long I had a nice proof-of-concept. When I showed most people the demo they found it amazing. However, I swamped with irrelevant college coursework and I had to discontinue serious development. After school ended, I realized I would never finish the desktop version: I would never stop adding features.
I then realized that people who have iPhones would probably enjoy the app. I personally don't own an iPhone. I contacted some people over the Internet and found two people willing to loan me equipment for developing an iPhone application. Alex Alba lent me his iPhone for a week (In exchange, he got to use my really old Nokia brick phone). Kyle Coe/Sue Coe lent me their MacBook Intel with Leopard.
In one week, between work and school, I learned Objective-C, learned how to use the iPhone SDK, and finished the iPhone version of TrippingFest. Ironically, I still don't and probably never will own an iPhone.