Yes, this is true. My second level is a 2x2 with a 1x1 with another 1x1. I was just thinking my mom said that if I made my cage a little smaller(becuase I can barely get in my room) I could make 3 levels. So if I made my bottom level a 2x3, the 2nd and 3rd level a 2x3 could I house three in it...