Acknowledgements

I would like to acknowledge enlightening conversations with Stuart Rice, Tom Witten, An-Chang Shi, Jean-Pierre Hansen, Phil Pincus, Adrian Parsegian, Rudi Podgornik, Tong Zhou, and Sue Coppersmith. Many of the experiments discussed above were performed by John Crocker, Amy Larsen, Jessica Weiss, and Eric Dufresne and many of their insights also appear herein. This work was funded in part by the National Science Foundation through Grant DMR-9730189, and in part by a fellowship from the David and Lucile Packard Foundation.