The term is from 红楼梦/Dream of the Red Chamber chapter 35. I have found several translations and none is any more helpful that this: four sets of moulds for soups. I do not know what soup molds (or moulds) are in English.
These ones have a decorative purpose which one translation expresses this way:
On the top, holes were bored of the size of beans. Some resembled chrysanthemums, others plum blossom. Some were in the shape of lotus seed-cases, others like water chestnuts. They numbered in all thirty or forty kinds, and were ingeniously executed.
But I have no idea what that really means. Do such molds exist today?