I taught myself GAMBAS over a weekend (previous VB 6 fan here and most likely showing my age -  ops: ).

Having never heard of the eight-queen puzzle, I was intrigued by the recursive method I spotted in the book Programming in Lua which is replicated on StackOverflow - recursion - The Eight-Queen Puzzle in Programming in Lua Fourth Edition - Stack Overflow.  To get a visual of what was happening, I built a simulator which really helped.  Here's a GIF of the program which is also hosted on Gitlab - https://gitlab.com/lea…gambas/eight-queen-puzzle for posterity:

UPDATE: Just thought I'd mention that I'm using GAMBAS 3.18.4 via PPA on Ubuntu 22.04.

(Click to enlarge)

For others (like me) who have never heard of the eight queen puzzle, here is a Wikipedia Link: Eight Queen Puzzle