For a history on this activity, you might enjoy the more thorough write ups from the first two years:
Premise is simple: polar graphs are neat, and I wanted a better way to present them.
The technology for doing this low tech activity has gotten better since the inception. Year 1 the kids squinted at TI screens and did their best. Year 2 we had a few iPads and upon assigning their graphs I required them to sketch a duplicate. Year 3 with an army of iPads and a printer, every student printed the necessary graph and used that hard copy.
Given two graphs and two chunks of sidewalk, present your graph.
The scale of the project always blows me away. A few of the kids will take a step back when they see how much ground a single class covers. Were you to own a small airplane, you'd be impressed at the coverage.
99 students participated, and we covered close to 1000 feet of sidewalk and there it stays until the rain washes it away.