My digital restoration of one of the two marble heads of Caesar at http://www.rmo.nl/onderwijs/museumkennis/klassieke-wereld/romeinen/de-voorwerpen/julius-caesar
The Rijksmuseum van Oudheden is the national archaeological museum of the Netherlands. It is located in Leiden. The face used is that of the Tusculum bust. Actually rectangles are coherent (see the discussion in this post.