I used Diffusion Circles from School Speciality Catalog for this lesson. You can also use coffee filters, but I do like the diffusion circles better. Standard water based markers...making sure you have a mat paper under the circle or your tables will be very colorful!! The students then scrunched up their mat paper into a ball and put the circle over it. They used a pipe cleaner to secure it in place(first time I used pipe cleaners for this project...was sooo much easier than string!!!) Use liquid starch in a spray bottle to sprits the form. This will allow the colors to bleed together & create a stiffer finished form(the diffusion circles have a bit of a stiffer form naturally than the coffee filters).