Three is a significant number in Tai Chi.
There are the three stages of development, Heaven, Earth and Man. The three outer coordinations and the three inner coordinations, which form the Six Harmonies. In Martial arts we have the Head,Hands and Feet.
In his seminal book, " The Tao of T'ai Chi Ch'uan ", the late Master Jou Tsung Hwa describes an exercise to help with remaining balanced, utilising three phases.
First, let your weight settle down.
Second, put awareness into the lower Dantien in the belly.
Third, put some light energy at the top of the head.
I found it very useful.