  The algorithmic self-assembly of shapes has been considered in several models
of self-assembly. For the problem of \emph{shape construction}, we consider an
extended version of the Two-Handed Tile Assembly Model (2HAM), which contains
positive (attractive) and negative (repulsive) interactions. As a result,
portions of an assembly can become unstable and detach. In this model, we
utilize fuel-efficient computation to perform Turing machine simulations for
the construction of the shape. In this paper, we show how an arbitrary shape
can be constructed using an asymptotically optimal number of distinct tile
types (based on the shape's Kolmogorov complexity). We achieve this at $O(1)$
scale factor in this straightforward model, whereas all previous results with
sublinear scale factors utilize powerful self-assembly models containing
features such as staging, tile deletion, chemical reaction networks, and tile
activation/deactivation. Furthermore, the computation and construction in our
result only creates constant-size garbage assemblies as a byproduct of
assembling the shape.
