  We employ three numerical methods to explore the motion of low Reynolds
number swimmers, modeling the hydrodynamic interactions by means of the Oseen
tensor approximation, lattice Boltzmann simulations and multiparticle collision
dynamics. By applying the methods to a three bead linear swimmer, for which
exact results are known, we are able to compare and assess the effectiveness of
the different approaches. We then propose a new class of low Reynolds number
swimmers, generalized three bead swimmers that can change both the length of
their arms and the angle between them. Hence we suggest a design for a
microstructure capable of moving in three dimensions. We discuss multiple bead,
linear microstructures and show that they are highly efficient swimmers. We
then turn to consider the swimming motion of elastic filaments. Using
multiparticle collision dynamics we show that a driven filament behaves in a
qualitatively similar way to the micron-scale swimming device recently
demonstrated by Dreyfus et al.
