Mirror – to all of us a familiar object we daily use. Aware of that or not, one average person spends about 55 minutes before a mirror. Still, it is not just used to watch our own reflection, instead it can be a useful ally when it comes to decorating space. Depending upon their size, number or a position, mirrors assist us in creating optical illusions which will influence how we perceive the space in which we live, i.e. they can make that space visually higher, broader, cosier or brighter than it really is. Different ambiences could be created if we use just one large mirror or several smaller mirrors placed to a wall or couple of walls. If we, for instance, place one big mirror to a longer wall of some narrow space like a hallway, this space can visually seem broader. Also, if we carefully think on its position in relation to other windows, paying attention to the light’s angle and reflexion, we bring additional daily light into darkened corners of the space thus creating seemingly open and larger space. Mirrors can be used in almost all interior spaces. Applied to furniture from its inner or outer side, or standing alone, mirrors serve a nifty trick when we want to stress or hide some details in space, making sure that the size and style of the mirror we selected corresponds to other decorative pieces in the room. Used alone or as a part of composition from more elements different in shape, dimension and angle-positioning, arranged so that can reflect certain elements in space we would like to emphasize, mirrors may create interesting play (interaction) of reflections. No matter if this is an artistic painting, plant, or some interesting piece of furniture, looking at their reflection in the mirror form different angles simultaneously shaping a different (new) view on the world around us. Since it is relatively easy today to find different types and styles of mirrors’ frames, including the ones with no frame, it is possible to play with their combinations, making sure they are compatible, these compositions (collages) can be placed on walls instead of pictures or photographs. Hardly one can make mistake when playing with mirrors in interiors – this decorative and practical element increases our visual footage of the room where it is “installed” contributing to its aesthetic value as well.