Shadow is the diminution alike of light and of darkness, and stands between darkness and light.
Leonardo da VinciJust as iron rusts from disuse, and stagnant water putrefies, or when cold turns to ice, so our intellect wastes unless it is kept in use.
Leonardo da VinciI am never weary of being useful... In serving others I cannot do enough. No labor is sufficient to tire me.
Leonardo da Vinci