Paving block with improved water run-through

Claim 1

A paving block having substantially flat and parallel top and bottom surfaces, a central portion which is a substantially equilateral triangle and three apex portions each being located in a region which would otherwise be the location of a respective apex of the triangle, there being three recesses, each located between a respective pair of apex portions, each apex portion having a first pair of walls each of which in part defines a boundary of one of the three recesses in the block and a third wall which defines an outer boundary of the apex portion, the third wall being shaped to secure an interfit between a recess of one block and an apex portion of an adjacent similar block, the interfit being incomplete and arranged to define one of a plurality of run-away holes in an array of laid blocks, wherein each wall of said first pair of walls is convex and wherein the third wall of each apex portion is in part defined by a pair of concave walls each of which has a curvature which is complimentary to the curvature of the convexity of the said pair of first walls.