TIL my grandma was right about the $4 thrift store mirror trick

My grandma came over two weeks ago and saw the plain builder-grade mirror in my hallway and just shook her head. She said she used to pop the frames off cheap mirrors and hang them a few inches away from the wall with a little wood block behind so the light hits different. I didn't believe her but I tried it with a $4 mirror from the Goodwill on 5th and it looks like a completely different room. The gap makes fake depth and the shadow line where it meets the wall reads like a real wood frame. I did the same thing in my bedroom with a $6 one and now I'm looking at every cheap mirror in the store like it's a project. Has anyone tried this with a bigger mirror over a dresser, does the gap trick still work at that size?