Tiles on a half-spiral staircase - who has experience with that?

Or the joint follows the path, thus basically maintaining a constant distance from the inner edge.

That was more or less my suggestion, exactly the other way around: to apply it not to the joint, but to the center of the tiles.

If I read correctly, the tiler did not implement what you had discussed and changed it on his own.

Why don’t you go there and tell him it was not agreed upon like that and he should redo it... it really doesn’t look nice, you can’t leave it like that?

Not much was discussed, except that I wished for only one joint per step, even on the long ones.

Now there are indeed more than one joint there, but he said it couldn't be done differently because he couldn't mix 60s and 80s due to the fire color.

He said it would have looked worse than an additional joint.

So now there are two 80s on the long steps, which created a small triangle. (My original idea was to mix 80s and 60s).

I think this also causes the joints on the long steps to be further out.

The front sides are all exactly 60cm from the inside. And the joints on the tread are mostly exactly between two front side joints.

The deviations on the long steps probably occurred because he used different formats there.