I have been playing about with a quilt block from Moda called MiniCharm
As you can see I managed to get some puckering on the seams. Not sure if this was the white fabric or my sewing.
Needed to try again
Using a different fabric seemed to help but still not happy. I think it will be possible to unpick this and save it.
I try again
This is much better, I double checked all the measurements on the pieces and feel happy with the points.