Then he took a cup, and when he had given thanks, he gave it to them, and they all drank from it.
(Mark 14:23)
It is expected that this cup should have a round form.
For this reason too the cranium is called gulgoleth, because of its being nearly round. Because every sphere rolls rapidly, every spherical thing was called galgal. Hence the heavens were called galgallim because of their being round - I mean, because of their being spherical.
(Maimonides, The Guide of the Perplexed)
But then note the irony: the disciples are drinking from this cup, during the Last Supper.
While on the real “cup” (=Golgotha), the Jesus has to drink, for a misunderstanding about the his real function:
Someone ran, filled a sponge with wine vinegar, put it on a staff, and offered it to Jesus to drink.“Now leave him alone. Let’s see if Elijah comes to take him down,” he said.
(Mark 15:36)
So Jesus predicted, during the Last Supper, that he would have offered to drink his blood on a real “cup”, the Golgotha or “Place of Skull”.