Sri Aurobindo
Letters of Sri Aurobindo
11. Visions and Symbols
When the colours begin to take definite shapes in the visions, it is a sign of some dynamic work of formation in the consciousness: a square, for instance, means that some kind of creation is in process in some field of the being; the square indicates that the creation is to be complete in itself; while the rectangle indicates something partial and preliminary. The waves of colour mean a dynamic rush of forces and the star in such a context indicates the promise of the new being that is to be formed. 
The blue colour must here be the Krishna light, so it is a creation under the stress of Krishna consciousness. All these are symbols of what is going on in the inner being, in the consciousness behind and the results well up from time to time in the external or surface consciousness in such feeling as the awareness of a softening and opening which you had, devotion, joy, peace, Ananda, etc. When the opening is complete, there is likely to be a more direct consciousness of the working that is going on behind, till it is no longer behind but in the front of the nature.