We are very grateful to our collaborators and friends Noel MacDonald, John Suh, Greg Kovacs, Ken Goldberg, and Danny Halperin for sharing with us the research surveyed in this paper.

The authors would also like to thank Steve Glander, Robert Darling, Christopher Storment, and all the members of the Stanford Transducers Lab; the members of Noel MacDonald's research team; staff and users of the Cornell Nanofabrication Facility, the members of the Cornell Robotics and Vision Lab (CSRVL), the members of Donald Lab at Dartmouth, Lydia Kavraki for fruitful discussions, and Jean-Claude Latombe for his hospitality during our stay at the Stanford Robotics Laboratory.

Support for our research was provided in part by the NSF under grants no. IRI-8802390, IRI-9000532, IRI-9201699, IRI-9530785, IRI-9896020, and by a Presidential Young Investigator award to Bruce Donald, in part by NSF/ARPA SGER no. IRI-9403903, in part by an NSF Challenges in Computer and Information Science and Engineering (CISE) grant no. CDA-9726389, in part by an NSF CISE Postdoctoral Associateship to Karl B hringer no. CDA-9705022, and in part by the AFOSR, the Mathematical Sciences Institute, Intel Corporation, and AT&T Bell Laboratories.