Structural tube

1. A structure comprising:

a structural tube having one of a square, rectangular, and circular cross-section, the structural tube having a first stepped slot on a first side of the structural tube, a second stepped slot on a second side of the structural tube, a third stepped slot on third side of the structural tube, and a fourth stepped slot on a fourth side of the structural tube, each of the first, second, third and fourth slots extending from an end of the structural tube;

a first cross member, the first cross member having a first region configured to act as a gusset plate, a second region spanning a width of the structural tube, and a third region configured to act as a stiffener plate, the first cross member including a first surface and a second surface facing the first side of the structural tube and the third side of the structural tube, the first cross member penetrating the first and third slots;

a second cross member, the second cross member having a fourth region configured to act as a gusset plate, a fifth region spanning a width of the structural tube, and a sixth region configured to act as a stiffener plate, the second cross member including a third surface and a fourth surface facing the second side of the structural tube and the fourth side of the structural tube, the second cross member penetrating the second and fourth slots; and

an end plate, the end plate having a first tab in the first slot, a second tab in the second slot, a third tab in the third slot, and a fourth tab in the fourth slot.

2. The structure according to claim 1 , wherein each of the first slot, the second slot, the third slot, and the fourth slot are stepped slots having two different widths.