Figure 2.

(a) and (b) Evolution of a multi-colloid system, containing 40 disks with diameter $\sigma =2$ in (a) 160 disks with diameter $\sigma =1$ in (b). In both systems the same area is covered by disks, the needle density is ${\rho }_{\text{n}}^{\prime }=20$. To generate the initial configuration we place the disks overlap-free and add needles where they fit until the desired density is achieved. The series of snapshots shows the self-assembly of the disks first in chains and then into hexagonal clusters. We show partly periodic images, extending the original system indicated by a black square. (c) and (d) Also in high density systems (${\rho }_{\text{n}}^{\prime }=100$) disks align with the director. (c) and (d) have different initial configurations, shown in the left column with disks at 0 and 45 angles. Right column shows equilibrated state. (Figure created using gnuplot 5.2 (http://www.gnuplot.info/), inkscape 0.92.5 (https://inkscape.org/)).