Thank you for the info. Is there a documentation of hs_color and xy_color ?
Just for info. The model I talk about is this one :
Hue is a value from 0 to 360 (degrees on the wheel). That makes it easy to say the next colour is the actual + 1, or 10 … if value > 360 than value = 0 and you can cycle through all colours. In my example the 2nd lamp has the opposite colour of the first (example 60 and (60+180) = 240. Both rotate by the same value.