Staircase

3D Spiral Staircases wind around a central 3D pole. The 3D Spiral Staircases typically have a handrail on the outer side only, and on the inner side just the 3D central pole. A 3D squared 3D Spiral Staircases assumes a square 3D stairwell and expands the 3D steps and railing to a square, resulting in unequal steps, larger where they extend into a corner of the 3D square. A pure 3D Spiral Staircase assumes a circular 3D stairwell and the steps and handrail are equal and positioned screw-symmetrically. A tight 3D Spiral Staircase with a 3D central pole is very space efficient in the use of floor area.