A nice DIY experiment [knolleary.net] of how graphs can be represented with paper - not on paper, but with paper. Having a physical, paper-based embodiment of the raw data means one can touch it, feel it, grope it, which in the end might help the understanding.

More information can be found here and a how-to description can be downloaded here (PDF).

For more alternative, physical or edible pie charts, see:
- Chocolate fudge pie chart
- Pizza box pie chart
- Pie chart already eaten