# Inversion Puzzle

You can describe your inversions however you like. I think an ordered grid from the center (n,m) is easy to understand (doesn't matter where to start due to radial symmetry), or an image

• Neat puzzle! Is there a reason why the black regions are not uniform? It's not important, but it makes the puzzle slightly harder to solve using an image editor because it breaks floodfilling. – noedne Apr 9 '19 at 21:42
• Because I drew them in procreate. Thats a good point I'll remember that next time I make something like this – Artemmm Apr 9 '19 at 21:45

## 2 Answers

My solution is

2 moves to make the inversions - was very slow to make this horrible graphic!

• Correct! Also works with most circles and sections – Artemmm Apr 9 '19 at 22:49
• I would have drawn it quicker by making a fresh start with an 8 x 4 rectangular grid. I was able to floodfill the white areas with black but somehow not with black areas with white. – Weather Vane Apr 9 '19 at 22:51
• Black areas are shaded. Will make it easier next time. You can see the shading better here m.imgur.com/Sg5RLNi – Artemmm Apr 9 '19 at 22:58
• My apologies to @PiIsNot3 because I inadvertently copied his final image, mistaking it for the one in the puzzle. Corrected. – Weather Vane Apr 9 '19 at 23:00

EDIT: I found an even better

2 inversion solution:

And of course, this is the optimal solution because you obviously can’t get to the end with only one inversion

Original answer: I can do it in

6 inversions

by

inverting a set of 4 non-adjacent big triangles (the ones that go BWBW or WBWB), then inverting the 2 black rings that result from that. (Will update with a visual later)

• Correct! Not sure who got it first but both correct – Artemmm Apr 9 '19 at 22:51
• @ArtemLugin this was first with the 6 solution, I was working on the graphic for my 2 solution when PilsNot3 announced he had found a 2 solution. However I didn't post anything until mine was ready. – Weather Vane Apr 10 '19 at 7:11