I bought four 30 inch square mirrors to fit on my walls as part of a square formation (60 in by 60 in), but eventually used only three as part of a triangle formation instead, as 60 x 60 is just too square and fixed a feature for my living room.  he triangle gives the room a touch of modernity and mystery together.  The formation perfectly reflects the other side of the room so that when guests walk in they get an expanded viewpoint, seeing artwork that nearly reaches the 12 foot high ceiling.  Part of the reason I wanted the mirrors stacked was to take advantage of the height of my high ceilings (12 foot), and "work" the 7 feet that sits above chair rail and sofa opposite the artwork as the room itself is small.  I also love that they're frameless and have rounded edges as it doesn't lend itself to any specific room décor, there's no hardness.  And the beveling is so well-done that it speaks quality and oddly has a kind of prism effect.