Estimated Time:
hour(s)

Materials:
Plastic cups: red, white and blue...approximately 800 of them, in the example I saw.

Description:
This seems to have originated in Hawaii, which is home to several military installations.

Someone figured out that right-sized plastic cups would fit securely into the mesh of chain link fencing...which can serve as a Grid for construction of a huge 'flag', visible from quite a distance.

Instructions:
Check the market for red, white and blue cups, and try a package before you invest in 800 of 'em ;-) I haven't seen such a flag up close n' personal (only a newspaper pic) but I am guessing it is the child-sized, vs. the Super-Bowl beer sized, plastic cups ;-)

Once you have determined that the mesh and the cup size are a Go, it becomes a perfect Math Class problem, as students examine the fence for "how many cups high?, plot the design on graph paper to make it proportionate, and then count how many of each color needed, how many packages of each, costs, etc.

You then have to divvy up the construction job/insertion of cups, so that everyone has a chance to Help and be a part of the project.

Other comments or suggestions:
You might want some extra cups, in case of future breakage. I am not sure how long such a Work of Art endures, but it does have the advantage of being water-proof.