The list of links grew and grew and just keeps growing, so it makes sense to divide them up. It makes it easier to find the ones that might be useful.

Many sites are hard to classify since they often cover a wide range of material, from tessellations to philosophy etc. The sites have been ordered according to the reason they were found to be useful in the first instance. If it was tiling then it gets listed under tiling even though the vast majority of the site might be into something else.

As new links get added and as the usfulness of old links changes so will things get moved around...