After studying Indian Mandalas (for some classes, I introduced the art; for others, it was a follow-up on a sub lesson), my 4th grade students watched the YouTube movie Flowers are Fun, which shows a person drawing a Mandala design. We talked about radial symmetry, and how a design can look really complicated if you repeat simple swirls, lines, and shapes around a circle design.
Next, the students brainstormed things you can find in nature that have radial symmetry. I let the students keep coming up with ideas until someone said, "a snowflake!" Then, we talked about how snowflakes always have six points, and if you draw a mandala with 6 points, it could look like a fancy snowflake.
Next, I gave the students 4 1/2 by 6 inch paper with a six-pointed asterisk on it (printed very lightly in gray). I told the students the lines were to guide them in making their snowflakes balanced, but the gray lines are not part of the finished design.
The students used markers to draw snowflakes on the guide paper until they came up with a design they liked. Then, we taped the paper to a piece of foam, and traced over every line in the design with a ballpoint pen, pressing hard. I had to remind the students to not trace the guidelines.
Then, we peeled off the paper, and inked the foam with silver block printing ink. The students printed multiple times on 6 by 9 inch paper (just on one half), and then when we were all done, they could fold the paper in half, and use their prints as Christmas cards!