The word 白驹过隙 is formed by the sequential combination of four characters: 白 (white), 驹 (colt), 过 (to pass), and 隙 (crack). Literally, it constructs the image of a white colt passing swiftly by a narrow gap, which serves as a metaphor for the rapid passage of time. Each character contributes directly to this concrete visual, with 白驹 specifying the subject, 过 describing the action, and 隙 defining the spatial element, together creating a figurative expression of something fleeting.