# Red Perimeter 1 – Extend the Pattern

Given $$n \times n$$ squares made out of $$1 \times 1$$ unit squares with the perimeter of the $$n \times n$$ square painted red, some of the $$1 \times 1$$ squares will be painted on 2 sides, some on only 1 side, and some won't be painted at all.

How many unit squares will be painted red on only 1 side in a $$4 \times 4$$ square (not pictured)?

This problem is part of Arron's set The Red Perimeter.

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