Literature Reference: 古人已用三冬足，年少今开万卷余。—— 《柏学士茅屋》 The ancients have already spent three winters in study, and the young now open thousands of volumes. Source from 'Bai Xueshi Maowu' by Du Fu.
三: meaning to think thrice, or deep thought. acting after thinking thrice, leads to smooth and successful endeavors, earning the trust and confidence of many.
冬: Like the winter sun, it brings warmth and a sense of intimate comfort.
Meaning: Three winters symbolize a long process of diligent study and accumulation of knowledge.