The world is broad and free, but the directionless mouse (implying a confused person) is afraid. It runs around freely and confusedly until it is "lucky" to see two walls (implying a confused person). Referring to the loss of freedom and the arrival of restraint), however, these two walls begin to close together, and at the end of the road is a mousetrap (the arrival of the end). What the cat said (implying a person with direction) means: Life is not hopeless. You push yourself to a dead end until you die. . .

The rat here implies a weak person who has no direction, living on a confused and directionless road of life, scurrying around until he perishes.

The cat alludes to a strong person who has a direction and pursuit. It knows what it wants to do, so that it will not lose itself in the ocean of life and destroy itself like a mouse.