Addendum to: Nature, published online 14 February 2018.

After the publication of our Letter, we were made aware of some pioneering simulations by Prestipino Giarrita et al. that investigated the icosahedral ordering of defects in assemblies of hard particles packed on the surfaces of spheres1,2. This work anticipated the notion that lattice defects were an inevitable part of ordered structures assembled on spherical shells, and they defined a pair defect-density correlation2, gdef, similar to the g55 function that we plot in Fig. 2a of our Letter. This work1,2 represents a solid contribution to the field and merits wider recognition.