Building block

Abstract

A building block includes two perpendicularly connected square frames, and a hypotenuse frame extended between outer edges of the two square frames. Each of the square and hypotenuse frames has an outer frame portion and an inner cross-shaped rib portion having a thickness twice as large as that of the outer frame portion. The cross-shaped rib portion divides a space enclosed in each frame into four equal divisions, which are four cavities on one of the two square frames; two diagonally opposite round connecting posts and two diagonally opposite cavities on the other square frame; and two diagonally opposite connecting protrusions and two diagonally opposite rectangular cavities on the hypotenuse frame, so that a plurality of the building blocks could be assembled together in different manners to form changeful shapes via engagement of the cavities with corresponding connecting posts or protrusions.

Dependencies are inferred from the claim text.