It has been said in so many words that Jazz is the epitome of variations on a theme. I believe that good Tai Chi can encompass such spontaneous embellishment or variation of a preexisting theme as well. Note in the video link above what a beautiful combination of movements goes into Cloud Hands. Also an epitome of good ways to practice by practicing one move over and over. That first walking step is a thoughtful addition which mobilizes the internal because of that initial stretch where you see "ah ha" expressions on smiling faces. That first motion made by Master Hwa is a quarter body movement that connects the arm to the core. His motion of pulling something with both hands is what he actually does gently to arms of students so they can feel a connection from arm to the core. The great thing about this is that the more you initially stretch forward, the more you feel the stretch pulling backward.