River pebbles are used for a variety of purposes, both outdoors and indoors. They can be sorted by colour and size, and they can also be polished to improve the texture and colour. Outdoors, pebbles are often used for landscaping, construction and as decorative are often used to cover walkways and driveways, around pools, in and around plant containers, on patios and decks. They are also used to create water-smart gardens in areas where water is scarce. Small pebbles are also used to create living spaces and gardens on the rooftops of buildings. Indoors, pebbles can be used as bookends and paperweights. Large pebbles are also used to create "pet rocks" for children.