Abstract: Blocks 20 interlock at cutouts 24 to form a row of blocks. Waves with wave crests 44 propagate in the direction of arrow A towards the blocks. When the waves impact the row of blocks 20,the alternating peaks and troughs formed by the edges 22, facets and steps of blocks 20 cause reflection of the waves from a plurality of point sources such that the reflected waves have circular wave fronts 46. The wave interference of the circular wave fronts 46 in the regions shown by reference numeral 48 results in a phenomenon known as near field diffraction. Circular wave fronts 46 also interfere with waves 44. This reduces the wave intensity impacting the blocks.

Abstract: Blocks 20 interlock at cutouts 24 to form a row of blocks. Waves with wave crests 44 propagate in the direction of arrow A towards the blocks. When the waves impact the row of blocks 20, the alternating peaks and troughs formed by the edges 22, facets and steps of blocks 20 cause reflection of the waves from a plurality of point sources such that the reflected waves have circular wave fronts 46. The wave interference of the circular wave fronts 46 in the regions shown by reference numeral 48 results in a phenomenon known as near field diffraction. Circular wave fronts 46 also interfere with waves 44. This reduces the wave intensity impacting the blocks.