Power of a metaphor

In a metaphor, there are two things: the tenor (the target domain) and the vehicle (the source domain). The former is the thing described---the subject of a metaphor, and the latter is a means that describes the thing. In reality, metaphors surround us because what we compare with is from nature. We live in nature, seeing, feeling, touching, and experiencing things therein. We express ideas and thoughts via metaphors or similitudes. For example, how can I best express gratitude to my mother other than through a metaphor? I can say from my heart that she is heaven, sea, soft wind, and earth. What my mother means to me is ineffable, so I use certain metaphorical images to express my thinking. Metaphors are evasive to some degree, and no one can understand fully what is expressed in them. As such, the power of a metaphor lies in its freedom that defies any fix of the meaning.