  We report Monte Carlo simulations of a simple off-lattice patchy-particle
model for DNA `bricks'. We relate the parameters that characterise this model
with the binding free energy of pairs of single-stranded DNA molecules. We
verify that an off-lattice potential parameterised in this way reproduces much
of the behaviour seen with a simpler lattice model we introduced previously,
although the relaxation of the geometric constraints leads to a more
error-prone self-assembly pathway. We investigate the self-assembly process as
a function of the strength of the non-specific interactions. We show that our
off-lattice model for DNA bricks results in robust self-assembly into a variety
of target structures.
