Sunyata (Emptiness) =
Anicca (Impermanence) +
Anatta (Unsubstantiality; Non-self)
Anicca refers to all physical and mental phenomena
not being with solid fixed nature
at any time as they change from moment to moment.
Anicca describes phenomena in terms of nothing physical and mental enduring in time,
Anatta refers to all physical and mental phenomena
not being with solid fixed nature
at anywhere due to Anicca.
Anatta describes phenomena in terms of nothing physical and mental enduring in space.
E.g. there is nothing we can point to in our body and mind,
or in the universe out there, that does not abide by Anicca and Anatta.
There is nothing physical or mental that stays affixed, unchanging in time and space.
This is why all phenomena are characteristics of Sunyata.
Related Article:
How to Attain Universal Freedom
http://thedailyenlightenment.com/2011/08/how-to-attain-universal-freedom