placing objects next to eachother and in corners

It could be that whoever made the house used the cheat 'moveobjects on' which allows you to put items pretty much anywhere (really close, on top or even in eachother!). You can try it, but it can make  sims interactions with the items glitched 🙂

Also, just to clarify what the person above said, the cheat is "moveobjects on" (without the quotation marks).