Animation of the formation of the Si(111) 7x7 surface reconstruction 

This whimsical animation almost certainly has the lowest educational-content-to-coding-effort ratio in this website, but it really does look very cute… 

It begins with nine atomic layers of the (111) diamondlike fcc structure of silicon. The top three layers are then allowed to morph from their bulklike configuration and relax into the famous 7x7 surface reconstruction, using the coordinates provided in the paper by K.D. Brommer et al., Phys. Rev. Lett., 68, pp 1355 - 1358 (1992). Colour coding according to the height of each atom in the reconstruction aids in visualization. Three colormap versions are given. Just comment out whichever one you don’t want to use. The input file with these surface-reconstruction atomic coordinates can be found here.