I found a very simple way to describe a spiral:

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1

I found a very simple way to describe a spiral:
radius = sin8( counter1 ) >> 5;
x = sin8( counter2 ) * radius;
y = cos8( counter2 ) * radius;
http://www.youtube.com/watch?v=Te0fvR0QfTw

2

Neat. To normalise the speed, you could scale counter2’s increments by dividing them by 2PIradius.