Enclosure Size Question

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I'm planning on making a "second level" in his new enclosure that would give him more floor space and that opportunity to climb and get more exercise. I was thinking of making the second floor above the main ground floor though, and it's a little hard for me to visualize the "false floor"/basement you're talking about. Would you by chance have any example photos of what you're talking about?

I think my 3x2x2 is set up similarly to what Boger describes.