A paving stone of a square block including four lateral edges, four angled corners and a central hole. The four lateral edges of the square block each have a v-shaped notch formed therein mesial the angled corners. The paving stone also including a plurality of groove-like recesses extending between the corner of the v-shaped notches and the corners of said central square hole to form a paving stone having the appearance of four separate octagons.
A structural unit includes a body having a plurality of exterior surfaces, at least one receiving arrangement provided on at least a portion of the body, and at least one positioning member connected to the body. The at least one positioning member is separable from the body and configured for interaction with the at least one receiving arrangement.