Mosaic from a Roman Villa at Olmeda, Spain. Look at the Solomon's knot over on the right had side. Why are these ones smaller? They appear to have the same number of lines in each strand, as far as I can see, so are the tesserae smaller? Did they start on the right and then realise that they had more space than they though for the motifs so the started to make them bigger?
Image copyright Valdavia (Wiki creative commons)