An interesting piece on the origin of the marbles used in Baia, Italy.
Deciphering a Roman geometric mosaic pattern can sometimes leave you with a number of choices. The pattern is distinct from the geometry, You can have the geometry of the mosaic worked out but still not be completely sure about the pattern.
Look at the two drawings below. On the right you can see by the way that I have coloured in the mosaic that it is made up of eight interwoven heart shapes which also create two interwoven squares.
On the left, by following the green arrows you can see that this pattern can also be just one continuous strand. Unless the original has distinct strand colours, as in the example on the right, then you just have to take a guess.