<Li> Opus sectile: A major shape (e.g. heart, letter, cat) is formed by a single tessera, as later in pietra dura . </Li> <Li> Opus classicum: When vermiculatum is combined with tessellatum or regulatum . </Li> <Li> Opus circumactum: Tesserae are laid in overlapping semicircles or fan shapes . </Li> <Li> Micromosaic: using very small tesserae, in Byzantine icons and Italian panels for jewellery from the Renaissance on . </Li>

What were mosaics used for in ancient rome