The eight - floor concrete building houses a bunch of different room types accessed by stairs or a cramped lift. (travelfish.org)
First grade is a year to explore and introduce a number of different concrete building blocks of math, such as problem solving, operations and number sense. (verywellfamily.com)
Once, after weeks looking at ambiguous figures, I found solid objects, even concrete buildings, flipping in front of my eyes! (newscientist.com)