J.E. Avron, O. Kenneth and D.H. Oaknin
Pushmepullyou: An efficient micro-swimmer
(24K, LaTeX with 2 eps figures)

ABSTRACT.  The swimming of a pair of spherical bladders that 
can change their shape is elementary at small 
Reynolds numbers. If large strokes are allowed then the swimmer 
has superior efficiency to other models of artificial swimmers. 
The change of shape resembles the wriggling motion known as {\it 
metaboly} of certain protozoa.