The connotation of life refers to a kind of phenomena that naturally appear in the process of the development and change of the universe, such as self-growth, reproduction, feeling, consciousness, will, evolution and interaction. Its extension can include self-replicating amino acid structures produced by biochemical reactions, and can also include fungi, bacteria, plants, animals (people). As far as the future development possibility is concerned, the machines manufactured or upgraded by people are complicated to a certain extent, and have some basic attributes that are in line with the connotation of life.
In addition, as far as the current conservative definition of life is concerned, the known life evolved from nature has more obvious fractal characteristics, which is more common in the currently defined inanimate natural phenomena. Therefore, although it cannot be said that all fractal structures are life, all life structures are fractal, which is a widely applicable and important measure.