Form is designed to be abstract and flowing.
It shapes and moves your body in a rounded fashion that mimics water.
There are no sharp corners or angles.

As your skill grows, you begin to feel as if the form is moving by itself. 
The divide between your mind, body and tai chi blurs.
Sometimes you complete a sequence or perform an application with no sense of what just happened or what you did.
This is good.
It reflects a condition of meditation.
We call this 'sung'.