Just a quick, Halloween-inspired lesson and project to reinforce the concepts of symmetrical balance and positive/negative space with the 4th graders. We started with a 12 x 18 sheet of black construction paper and a 9 x 12 sheet of orange. Students drew half of a jack-o-lantern on their orange sheet and cut it out. I challenged them to cut out their pumpkin's eye and eyebrow with an X-Acto knife, a new tool for most of them. (Despite the utility of the X-Acto, I'm hesitant to ask elementary students to use one after the Great and Horrible Soap Carving Project of 2012 -- seriously, it wasn't that bad, but we did go through more than a few bandaids.) Elements that were cut out of the orange had to be placed onto the black half of the jack-o-lantern so that the entire image would be as symmetrically balanced as possible.
If students had time left in the class period, they used black and white colored pencils to add symmetrical designs to their jack-o-lanterns.