Because they send me pictures like the ones below.
Friends, Ryan & LeighAnn (my favorite designer I'm always mentioning) just moved into a new house in Kentucky. And they have a basement. It might be the size of my entire NYC apartment, but that's besides the point. They are working on the spacial arrangement of the basement and sent me a few pictures.
And what did they use to layout the potential couch sectional?
Oh, you know. Just some toilet paper.