Tiles made of a resilient material bear an irregular rippled surface shaped so that the ripples pass from one tile to another without discontinuity. The rippled surface is taken from a natural surface such as beach or river sand which has had water flowing over it. Applications include covering the surrounds of swimming pools and areas where play or gymnastics occurs. The resilient material may be new or recycled rubber. The tiles may take the form of elongate strips, supplied in rolls.