I've done mandalas a number of different ways over the years and here is one variation although it's a bit tedious for the teacher because of the amount of photocopying involved. Students draw patterns and/or shapes in their 1/8 circle section with a black fine liner. The next step is to photocopy their section three times (their original is the fourth) and then use the reverse feature on your photocopier four times to get the mirror image. Once the kids have cut out all of their pieces they glue them onto a larger piece of paper. They just love watching their kaleidoscope patterns emerge. It takes some of them a few attempts to realize they need to alternate the original and the mirror image but eventually everyone figures it out.