I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "On the difference between the ideals of architecture and mere construction, the renowned 20th-century architect Le Corbusier wrote: "You employ stone, wood, and concrete, and with these materials you build houses and palaces: that is construction. Ingenuity is at work. But suddenly you touch my heart, you do me good. I am happy and I say: This is beautiful. That is Architecture"."? 

What is used to make houses and palaces besides stone and concrete?