To rotate or not to rotate.

My head has been going from confused to understanding to confused again and I think now I understand it a bit.

What am I talking about? The cutting pattern.

Because the drawing on this puzzle is so simple, it is hard to find pieces according to the image. It's easier and faster to try and find the same shaped pieces. To do this efficiently I need to figure out how the cutting pattern is repeated over the whole puzzle.

The day before yesterday, I told Pim that I had found out that the pattern rotated 180 degrees. So the right top corner of Image 26 matched a bottom left corner of an other image.

But then yesterday, when I was trying to figure out what images I saw this in, I saw that top right corners of both images matched. So I thought I was confused the evening before and didn't mention it in my blog, I even told Pim that apparently my crazy idea of rotation was just confusion.

Than today I was confused again because suddenly the pattern was rotated again. Turns out I was looking at 3 different images: the top right corner of Image 18 matched Image 26 AND the left bottom corner of Image 3!

Since I already have found pieces of the same shape I tried to figure out to what image they belonged. With the rotating pattern and the fact that pieces of different images get mixed sometimes, it is really hard and hair pulling sometimes.

So I know for sure that the patterns of Image 26 and 27 are 180 degrees turned. And Image 3 has the same orientation as 27 but rotated to 26.

For now this is my conclusion:
Image 2 , 6, 10, 14, 18, 22, 26 and 30 have the same cutting pattern
Image 3, 7, 11, 15, 19, 23, 27 and 31 have the same cutting pattern too, but turned 180 degrees.

The question now is what about the others?

I will know for sure once I'm done with all the pink.