GPT-5.6-Luna (xhigh) missed level 4 on a 2×2

What the model saw

Each picture is the exact image the model was sent; highlighted: start.

startafter turn 1 · 1 movesafter turn 2 · 2 movesafter turn 3 · 3 movesafter turn 4 · 3 movesafter turn 5 · 5 movesafter turn 6 · 9 movesafter turn 7 · 9 movesafter turn 8 · 13 movesafter turn 9 · 17 movesafter turn 10 · 17 movesafter turn 11 · 17 movesafter turn 12 · 25 movesafter turn 13 · 26 movesafter turn 14 · 34 movesafter turn 15 · 38 movesafter turn 16 · 42 movesafter turn 17 · 48 moves