Rectangles solution

[macta]

This is quite an interesting problem

[bencoman]

Brute force is quite a valid approach and is the only one I could think of for a while. Then reviewing Array2D >> isLineAt: another concept came to mind...

1. Generate horizontal line segments and validate pairs as possible rectangle sides
2. Generate pairs of vertical line segments and validate pairs
3. Combinatorially compare the two collections

(not advocating you change yours, just sharing)

[macta]

Your comment about generate line segment permutations is exactly what this solution is doing (maybe its a bit more obvious now) - it finds square permutations (based on the + corners), and then validates if they actually exist because they are correctly joined by "-" or "|" lines. (Probably worth saying this very text in the class comment actually)

[Bajger]

Solution moved and adopted for v3 in PR: https://github.com/exercism/pharo-smalltalk/pull/661