Understand what RadialPhase does to my RadialStim

Hi,

I’m creating and experience where rings are either contracting and expanding at different speeds.
To that extend I use the functions RadialStim with a RadialCycles of 10 and either increment or decrement that stim by applying a RadialPhase of either .05, .1. That works like a charm. But I’m having a hard time understanding the functions.

In the documentation it says for RadialPhase : " Set the radial phase of the texture (wraps 0-1). This is the phase of the texture from the center to the perimeter of the stimulus (in radians). Can be used to drift concentric rings out/inwards."

Because now I find myself wanting to calculate the Frequency of the motion of these stimulus but there isn’t much else explained. So I don’t really get what happens to my stimulus even though it works fine.
Does anyone have a deeper understanding of the RadialPhase argument ?

Thanks for your time,
Cheers,