In my post about brick repeat, I did not put in a repeating pattern. We had our design class today and had it explained. I think I got it: here is my attempt to explain it.
The pattern is laid out in a clear repeat horizontally, that is, the sides of the blocks will match exactly (the circles).
The blocks will then be moved across by half the block size in the row below, in a brick pattern. (I have made the lines around the blocks dark so that you can see them clearly, they would not be visible in a good brick repeat system.)
The partial star in the top right corner will match, in the vertical plane, with the partial star in the bottom left corner of the row above.
So, in this design, the row below has elements that seem to protrude into the row above and are shifted half a block across.
To put it another way, the sides of the block must match on the horizontal plane and the diagonal opposite sides must match in the vertical plane.
Maybe it's too late at night for me to be trying to verbalise this!