Trapezoid, circle, triangle. Discussion about the shapes of winding stairs can encompass all of the school algebra

One only needs to adorn it with some beautiful epithets and one can write a high school final paper about the winding stairs. But seriously, what you should know is that their support structure is based on central pillar (minimal diameter 140 mm), and the steps are positioned within circular or square framework.  

Surrounded by smoothly bent line of handrail (the best is the bar balustrade BS-1), it crowns our composition. The steps can be shaped as triangle or trapezoid.

One should however keep one’s imagination in check, and avoid all breakneck attempts to hoist a sofa, or some other large object, as they are surely doomed to fail, despite your best intentions, or highest bets. It’s because the winding stairs have – bear that in mind – only one function: communication. It is nevertheless the most important function of stairs, and therefore – considering all accommodations with limited space - they are the number-one choice and hold a total monopoly in this domain.