A system for assembly and attachment between structures for the formation of furniture. Composed of polymer injected pieces that fit together onto a principle module by means of a 90° turn. Ideal for reducing the number of tools for the manufacture of the different connections, and it increases the number of solutions for each type of connection and piece of furniture desired. Allows for less packaging material and facilitates transport. The polymer connections can be attached to a range of different materials (steel tubes, wood) and shapes (circular, square), in addition to offering combinations between colors and finishes.