There is a reason why sin(X) is an input property. :p
In the "swiss cake roll" the circular nature of the classes suggests using a sin or cos function, and the fact that they spiral out suggests also inputting magnitude information. Sure, you can just add more neurons that will end up computing the same thing, but we might as well give the computer a head start when we can.
I'd quite like if you could define your own input patterns and data sets.