The tablecloth shows alternating concave and convex folds..… Two little serving platters have eels garnished with fruit slices. They have no obvious religious or iconographic meaning; however, river eels were popular in Italy at the time, and we know that Leonardo, although usually a vegetarian, put “eels and apricots” on at least one of his shopping lists.
All told, The Last Supper is a mix of scientific perspective and theatrical license, of intellect and fantasy, worthy of Leonardo.
from Leonardo Da Vinci by Walter Isaacson (2017). Recommended.