Abstract: A resilient open-comparted three-dimensional structure suitable for use as a ground surface covering comprising an interlocked assembly of two pluralities of strips respectively formed at intervals with apertures and profiled regions which co-operate to interlock together the two pluralities of strips, a slit, slot, groove or the like extending into each aperture to facilitate interlocking of the two pluralities of strips. Two or more such structures may be superimposed on one another and a layer of resilient material may be provided between superimposed structures.