Puzzle #688 - Not So Simple Loop

I made this Simple Loop so long ago I don't remember why I made it. Let's see what my comments I have next to it in my puzzles spreadsheet say. "In PC, Rook mentioned not knowing parity for Sloop. So I made a Sloop using parity." Amazing insight, past me. The comment on the very next puzzle starts "this wasn't meant as an April Fools puzzle" so uh, oops 6 month delay.

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