The partitioning of deformation during continental collision is modeled in plan view using a thin viscous sheet simulation. In contrast to many previous models, an indenter is defined here as a zone of finite viscosity contrast to the foreland and aspect ratio. Deformation is enforced by pushing the southern boundary into the model region. It is shown that deformation is equally partitioned between indenter and foreland if the aspect ratio of the indenter is about 1:2, and it is about twice as viscous as the foreland. For higher-viscosity contrasts between the two plates, the partitioning of deformation between indenter and foreland depends more strongly on Argand number. The process of lateral extrusion is investigated by separating the lateral velocity field into a component that is due to lateral escape and a component that is due to gravitational extensional collapse. It is shown that lateral escape is roughly constant over time and is controlled by the convergence velocity and the obliquity of indentation.