a community of painters who lived during the late Hellenistic period. The murals emphasized domestic decoration, conveying the belief these people held that the Delian establishment would remain stable and secure enough for this artwork to be enjoyed by homeowners for many years to come. Mosaics Certain mosaics, however, provide a pretty good idea of the "grand painting" of the period: these are copies of frescoes. This art form has been used to decorate primarily walls, floors, and columns. Mediums and technique The development of mosaic art during the Hellenistic Period began with Pebble Mosaics, best represented in the site of Olynthos from 5th century BC. The technique of Pebble Mosaics consisted of placing small white and black pebbles of no specific shape, in a circular or rectangular panel to illustrate scenes of mythology. The white pebbles -in slightly different shades- were placed on a black or blue background to create the image. The black pebbles served to outline the image. In the mosaics from the site of Pella, from the 4th century BC, it is possible to see a more evolved form of the art. Mosaics from this site display the use of pebbles that were shaded in a wider range of colors and tones. They also show early use of terra-cotta and lead wire to create a greater definition of contours and details to the images in the mosaics. Following this example, more materials were gradually added. Examples of this extended use of materials in mosaics of the 3rd century BC include finely cut stones, chipped pebbles, glass and baked clay, known as tesserae. This improved the technique of mosaics by aiding the artists in creating more definition, greater detail, a better fit, and an even wider range of colors and tones. Despite the chronological order of the appearance of these techniques, there is no actual evidence to suggest that the tessellated necessarily developed from the pebble mosaics. Opus vermiculatum and opus tessellatum were two different techniques used during this period of mosaic making. Opus tessellatum refers to a redacted tessera (a small block of stone, tile, glass, or other material used in the construction of a mosaic) size followed by an increased variety in shape, color, and material as well as andamento––or the pattern in which the tessera was laid. Opus vermiculatum is oftentimes partnered with this technique but differs in complexity and is known to have