Movie S2.

From left to right: Fluorescently labeled microtubules confined to a 200 μm SU8 well with defects labelled (+12: magenta arrows, −12: blue dots with three prongs), the nematic director used to identify defects and associated order parameter field, flow field and vorticity (vorticity scale Ω = ± 1.1 s−1). Below: time evolution of defect counts and flow order parameter Φ.