Abstract: An interlocking block for interacting with other like blocks including a body having at least a front face, a rear face, a top face, a bottom face and a pair of side faces. The bottom face can have a plurality of substantially identical parallel transverse indentations but only in the bottom face. The grooves can have a constant cross-section and are spaced apart evenly between the front face and the rear face. There may be at least two substantially identical protrusions only on the top face, each protrusion being parallel with and in vertical alignment with one of the indentations, and receivable within a indentation of a like block. There are fewer protrusions than indentations.