I am still learning Lists and Trees at the moment.

I had created surface, divided it into different segments and I wanted to select the individual rectangles however the point list is not correct.

Eventually with the pointlist I plan to extrude certain rectangles together. Such as Rectangle 2 and 3 together at a different height as rectangle 1. or leaving some rectangle not extruded.

Dear @Birdreader
I hopefully understood your question correct.

the (spacial) order of the pointlist is given by the order of output of the “divide Domain ^2 component”.

use a rotated plane

I think the easiest way to get the desired sorting is to use a rotated plane for constructing the initial surface.
But this might lead to some confusion regarding x, y, u, v, or even violate the right hand rule… DivideDomain_Isotrim_02.gh (10.2 KB)

custom divide Domain

But maybe it is more recommended to not use the the “divide Domain ^2 component”. But combine 2 “divide Domain” each for u and v.
By reversing the output list and graft one of them - and flatten the result you can influence order. DivideDomain_Isotrim_03.gh (9.0 KB)
I like this approach more as it is does not mess with x,y, u,v.

resort / organize List

a third solution would be to resort the output List of Domains of the Divide Domain^2 component… but this seams more afford then the other approaches above.