I want to know the answer to the following question:
Kathmandu valley contains art made of metal, terracotta, wood and what other substance?
All the background I'm provided with is that "Kathmandu valley is described as "an enormous treasure house of art and sculptures", which are made of wood, stone, metal, and terracotta, and found in profusion in temples, shrines, stupas, gompas, chaityasm and palaces.". Is that enough to answer the question?