x1 is a bowl containing x2, made of x3.
The second slot is a bottlecap (2 that may not always exist">velbotsu'i), as with kabri, and should really say 'a bowl ›for‹ containing x2'. This word is part of a proposal to split kabri into two words, kabri being a container for liquids and bolva being one for food. A cup, a glass, and a mug are all kabri, but a ramen bowl or a pet bowl are bolva.