In Hinduism (Sanātan Dharma) the number - "three",.occurs in many instances
The Trimurtis - Brahmā, Vishnu and Mahesh (त्रिमूर्ति - ब्रह्मा, विष्णु और महेश ), the Three (Guṇas) Qualities - Sattva, Rajas, Tamas (त्रि-गुण - सत्त्व, रजस, तमस) , the Three Major Lokas (त्रिलोक), in the Ayurveda (आयुर्वेद) too, there are three fundamental bodily bio-elements - Vatta, Pitta, Kapha (त्रिदोषोपदेशः - वात, पित्त, कफ). The three threads that together constitutes the janeu - the upanayana thread.
So my question being, is there anything mentioned about the importance or significance of number "three (3)" in any of the Vedic Scriptures?
More importantly, does any Scriptures or School of Thought talks about any kind of relationship between the Three Qualities (त्रिगुण) & Trimurtis in terms of the three Ayurvedic Doshas ( दोषः) and/or the three threads of the janeu?