In 1963, The LEGO Group spun off a company called Modulex to create planning tools for architects, including a completely separate system of bricks. Though Modulex still operates today (still based in Billund, making modular corporate signage), they no longer manufacture little plastic bricks.
Nevertheless, Modulex bricks continue to be sought-after collectors’ items among LEGO fans. Some fans even have enough in their collection to reproduce contemporary LEGO sets, as Brixe has done with her collection.
Even though Brixe’s Modulex version is nearly a stud-for-stud clone of the LEGO set, this comparison shot shows the difference in scale between the two systems (LEGO on the left, Modulex on the right):