what would be the equation to a spiral which increments by the sum of the previous increment and the increment?
thus the turn gaps would be 0.1 0.2 0.4 0.8 1.6 3.2 6.5 13 26 52 104
what I have is r = 0.3 * theta^2 -1 + 30 * theta
but it doesent seem precisely what I am looking for