PSE3 does have define pattern.

But I don't know the steps to do this. I opened a 12x12 transparent background. Then I selected a small square of it and colored a dark background in it. I then drew a circle in the square and colored it something else. Then I went to Edit, Define Pattern. And then I didn't have a clue what to do next.

Sorry, but I guess I need further guidance.

Thanks again.
Elise