Logic Masters Deutschland e.V.

This is my second 9x9 sudoku. I think the Phistomefel ring is interesting, so I made this.

Rule:
Normal 9x9 Sudoku rules apply.

The grey lines are palindrome lines, which read the same in both directions. A palindrome line *CANNOT* pass through the same cell twice, but it *CAN* share cells with other palindrome lines, or even *OVERLAP*.

Cells separated by a black dot have a 1:2 ratio. Cells separated by a white dot must be consecutive. Not all dots are necessarily given.

P.S. The palindrome line doesn't turn at the crossing in box 3.

Hints:

• Let's firstly focus on the Phistomefel ring. Where could the midpoints of the palindrome lines on the Phistomefel ring be?
• A cell on the palindrome line in a corner box, e.g., R1C2 should appear at somewhere else on the palindrome line. Which midpoint could it use? Where could it be?
• R1C2, R2C1, R1C8, R2C9, R8C1, R9C2, R8C9, R9C8 appear at R3C5, R5C3, R5C7, R7C5. They are 4 distinct digits.
• After that, focus on R3C1. Then R8C5.

Click or tap the following image to play!