Three weeks ago I went to my kid's preschool, talked about how plants grow, and then we planted grass seed in cups. Today I went back and we decorated them and cut the hair. Rather than carefully sculpting most kids preferred to go for the buzz cut, or rather just cut and cut until we finally told them no more.
There's nothing quite like picking up grass clippings off a preschool floor after they've been accidentally coated in glue and stepped on by 9 kids. Sorry, Mr. Janitor!