The marks on a Golomb ruler are positioned that no two pairs of marks are the same distance apart.
A perfect Golomb ruler has as few marks as possible, and can measure every integer distance up to the length of the ruler.
There's no perfect Golomb ruler with more than four marks. This one is the biggest possible!
It's designed for dual extrusion: if you change the variable
false, it'll produce just the marks to fill in the gaps in the base model.