I've noticed T'ai Chi people like to talk about structure.
Sadly, in my view, everything is reduced to a form of mechanics. And yes, T'ai Chi does have rules and guidelines about alignment.
But a human being is an energetic entity, not just a system of pulleys and levers. So I view my T'ai Chi as a structure for energy. The energy gives rise to the structure.
This is one of the investigative purposes of my practise.