Share 'Rectangle false "packing" (Sample and example)'

I try here to answer from a question on discourse https://discourse.mcneel.com/t/fill-an-rectangular-area-with-predefined-elements/40728 Fill an rectangular area with predefined elements I add some difficulties to resist and to do it with Grasshopper and Anemone. I know it is surely more simple in C# or other program. Peter Fotiadis will be sad, but I did it in GH, it is quite long but it seems…