anything, as long as it's small

High, Size-Dependent Quality Factor in an Array of Graphene Mechanical Resonators

Robert A. Barton, B. Ilic, Arend M. van der Zande, William S. Whitney, Paul L. McEuen, Jeevak M. Parpia, and Harold G. Craighead

Nano Letters 11, 1232-1236 (2011)