I do not know the equation of this graph, but it reminds me of a graph that I came across last year when I was bored in math class. I was messing around on my calculator, and I found the polar graph setting. So I starting screwing around, just kinda typing in random stuff, and I came across a graph that looks almost exactly like some sort of bug, or misquito! I swear, I came across this graph by myself. I'm guessing that this graph might be online somewhere, but I did actually find it myself as well. Anyway, it doesn't help your question really, so I apologize. But, it is quite interesting. Heres the equation of the graph that looks like a bug:
Now, thats sorta hard to read. So to make it easier, lets say that:
Then it might be easier to read it as:
This graph shows up almost perfect on a basic Texas Instruments graphing calculator, but on higher quality graphing calculators (like my TI-Nspire) the graph looks alittle less like a bug. And, on graphing calculators that are less detailed then a standard texas instrument, the -step is too small for the all of the bugs wings to show up. But anyway, its pretty neat when you get it to work right.