Bhagavad Gita, Chapter 3, Verse 38

As fire is covered by smoke, a mirror by dust, and the embryo by the womb, so is this world covered by desire.

Clarity doesn't disappear all at once, it gets covered gradually, the same way smoke slowly dulls a fire's light.

These three images build from thin cover to nearly total: smoke can be seen through, dust just needs wiping, but a womb fully conceals what's inside. Desire is described as capable of the same range, sometimes a light haze, sometimes something that blocks judgment almost entirely.