It expresses exactly what is in its consciousness. We make use of the creative mind of God, so if we put the idea of lack into our consciousness, then that is what it expresses.
The expression of lack looks like whatever the mind that contemplates it says it is. This means you can think you lack and the thought/idea is put into reality however you choose to put it into your perspective.
For example, Lack of love looks however you decide it looks.