Fig. S1.

(Upper) MSD of a colloidal monolayer on a solid substrate. Accidentally, between 1 and 3% of particles were pinned to the substrate, which efficiently suppresses Mermin–Wagner fluctuations. The upper two curves are fluid; the circles indicate a system close to the glass transition, whereas the lower three curves are solid. Lower shows the density correlator (main text) for the same system (again, $qa=2\pi$).