Many kinds of mosaic games are available online. Some are available to test for free and don't require any registration or downloads. They range from a pentomino-style game in which players slide and rotate geometric shapes into place to create a pretty tessellation to an opportunity to design a mosaic similar to the ones underground in the New York City subway system.
Glassez Stained Glass
The Wellgames website offers six mosaic games in which players complete pictures by putting shapes together. The stained glass tessellation game called "Glassez" is ideal for teaching children about tessellations---repeating designs of geometric shapes without gaps. It is also useful for comparing attributes of various shapes, such as the fact that six kite shapes fit into one hexagon. Players earn points for each shape they slide into place and lose points when they select a shape for which there is no hole. Although matched with an opponent somewhere in cyberspace, the pace of the game is leisurely. Once the entire template is covered, the player receives his final score and can compare it to that of the opponent's.
Arbeia Roman Fort and Museum is in Northeast England. It is a re-creation of an original Roman outpost from AD160 built to protect access to the Tyne River. Online, the Arbeia Museum offers a game site, which notes that Romans were "great inventors, craftsmen and artists" as well as soldiers. Players are invited to create a mosaic similar to the ones decorating the homes of ancient Romans. Players slide different colours of squares onto a grid to create a colourful geometric design, then have the option of printing their art.
Mosaic Design and Illusions
Mosaic games available at the Kids' Game House website include MD Mosaic Design by Meyers Labs. There are no opponents involved. Players can choose from two mosaic-style games. One lets players create pictures by sliding different colours of squares onto a grid. Another more complicated game involves creating optical illusions through colour choices and placement of cubes.
New York Subway Mosaic
New York's Metropolitan Transportation Authority includes an MTA Mosaic Maker at the website of its New York Transit Museum. The museum notes that mosaics decorate many of the subway system's underground walls and asks players if they are aware of how much work went into creating these murals. Then players are given the opportunity to experience that effort on a smaller scale by filling in a 3-inch-by-4-inch screen with tiny squares, rectangles and triangles in various colours. It is time consuming but fascinating. One good approach is to divide the rubble of mosaic pieces into similar shapes and then begin building like a jigsaw.