  The behaviour of materials under spatial confinement is sensitively dependent
on the nature of the confining boundaries. In two dimensions, confinement
within a hard circular boundary inhibits the hexagonal ordering observed in
bulk systems at high density. Using colloidal experiments and Monte Carlo
simulations, we investigate two model systems of quasi hard discs under
circularly symmetric confinement. The first system employs an adaptive circular
boundary, defined experimentally using holographic optical tweezers. We show
that deformation of this boundary allows, and indeed is required for, hexagonal
ordering in the confined system. The second system employs a circularly
symmetric optical potential to confine particles without a physical boundary.
We show that, in the absence of a curved wall, near perfect hexagonal ordering
is possible. We propose that the degree to which hexagonal ordering is
suppressed by a curved boundary is determined by the `strictness' of that wall.
