The smart folks at Bathroom Break Games LLC have produced their first game called Sudoku Spin.
  The object is to get each ring and each sector (see the third image) to get the numbers 1-8.

Critical: each ring can spin. By my calculations, there are 64 permutations of arranging just the rings. Fortunately, if there is a conflict, it's highlighted in red.

I've tackled about 20 of the easy levels.

Numerous times: I've rotated the rings, then started filling in the grid, only to discover that my rings were wrong. Back to square one. Still, I wonder if there are multiple solutions in terms of ring rotation.

In a regular sudoku grid, every single square must be one and only a distinct number.  That's not the case with Sudoku Spin. If a sector is missing only a 3 and a 7, and they both land on the same ring, then the order is not important.
The graphics are very good.
https://itunes.apple.com/us/app/sudoku-spin/id1219674107"mt=8

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