Following is an excerpt from Dr. Steve Cash’s email to me:
There are many interlaced squares in Romano-British mosaics but very few interlaced equilateral triangles(hexagrams). The only ones I can cite are from Keynsham, Bristol, England. It is a grand villa with rooms of hexagonal plan at either end. One has a scheme of hexagons, six of which surrounding the central hexagon contain hexagrams. I assume that this is because of the shape of the room and the usual interlaced squares have been adapted on a purely geometric basis. The mosaic also features Medusa and is probably early fourth century.
Mosaic no II, 204.5 in Cosh SR and Neal DS 'Roman Mosaics of Britain
Vol II South-west Britain' 2005.