Quotes from the Tai Chi classics:
Flow like a river and be still as a mountain.
The root is in the soles of the feet.
The spine should be plumb erect from the coccyx to the crown of the head.
The chi or intrinsic energy should be stored below the waist.
Even the weight of a feather will set the body in motion.
When one part of the body moves, the whole body moves.
All Tai Chi movements emanate from the body centre.