or solve online (using our beta test of Penpa-Edit tools; use tab to alternate between a composite mode for line/edge drawing and a shading mode.)
Theme: Double Ring
Author/Opus: This is the 392nd puzzle from Thomas Snyder, aka Dr. Sudoku.
Rules: Variation of Spiral Galaxies. In addition to the standard rules, some circles are shaded gray and must belong to galaxies containing two gray circles, not one, with the circles in rotationally symmetric spots for those galaxies.
Difficulty: 4.5 stars
Time Standards (highlight to view): Grandmaster = 7:00, Master = 13:15, Expert = 26:30
Note: Follow this link for classic Spiral Galaxies puzzles on this website and this link for variations on Spiral Galaxies puzzles. If you are new to this puzzle type, here are our easiest Spiral Galaxies Puzzles to get started on. More Spiral Galaxies can be found in The Art of Puzzles 2.