House walls were plastered and painted with decorative panels, scenes from mythology or from daily life. Exteriors, and walls of the less wealthy, might be bright solid colors - often an ocher yellow-or marked and painted to resemble stone. Columns of stone, wood, or intricately shaped bricks, plastered and painted to look like stone, supported the roof. The roof beams were generally of wood, though stone might be used as well for short spans. Both Etruscans and Romans used the arch and the vault, though the possibilities opened up by arch construction were not fully explored until later. Wealthy homes might also boast of an interior garden, the peristyle garden, centered by a fountain and surrounded by a colonnade, columns supporting the roof of a covered walkway. Lead gutters and pipes channeled rainwater from the roof into storage for the household.