but adjacent sides with a matching diametrically opposed pair at the other end the legs 4 are placed in the apertures 7 and aligned such that a hole 15 at each end of one leg is in apostion with a hole at each end of the other leg each of the other two pairs of holes are facing in substantially the same direction the holes 15 at each end lie in substantially the same horizontal plane with respect to the holes at the same end on the other leg three hollow tubular sections 6a 6b and 6c are attached to each of the legs 4 by inserting an end into each of the holes 15 as shown in fig1 the tubular sections 6a 6b and 6c form a three sided upper frame with two sides substantially parallel 6a and 6b which are substantially perpendicular to a third side 6c a second substantially square bottom frame 10 is attached to the underside of each tubular section 6a 6b and 6c using conventional attachment means such a screws bolts or tie wires the second bottom frame 10 has two cross support legs 9 extending downwardly at an angle the cross support legs 9 extend diagonally with respect to the vertical plane formed.