In Marrakesh, by contrast, the flat landscape and ample space within its city walls meant that houses could have larger courtyards and fewer stories. Most older houses had only a ground floor, or at most an upper floor with a low ceiling used for storage. Larger and richer houses often contained riad gardens, which were more common in Marrakesh than in other cities. Houses were built in brick or rammed earth, with wood being used again for certain elements. Wooden corbelled arches seen in older houses became less common in more recent centuries and round or ogival brick arches were favoured instead. In turn, horseshoe arches became rarer after the 18th century. Walls were covered with plaster which historically had a rose, reddish, or yellowish colour, and sometimes enlivened with friezes of painted motifs. "Zellij" was used in reception rooms and around fountains. Window frames and doorframes are often highlighted with carved stucco. The carving of motifs into wood, on the other hand, became less common over time and by the late 19th century wooden decoration was limited to painted decoration. This painted decoration also evolved, however, increasing the use of floral motifs and typically employing a red background.