At the Registan ensemble in Samarkand, Uzbekistan, even the side walls are decorated with tile work. It's a highly regular pattern of interlocking diagonal squares with abstract arabic script in cream, blue and dark brown. But the regular pattern is broken by the placement of the windows and -in this picture- the long shadows cast by the roof beams and a small bush growing at the foot of the wall, creating a curious tension between regularity and irregularity.