Three demon brothers stood on one leg for a hundred years. Then for a thousand years they lived on air alone. Then they stood on their heads and meditated in that inverted posture for a further thousand years. Brahma, the creator, was pleased. He appeared before Tarakaksha, Vidyunmāli, and Kamalāksha — the sons of the asura Tārakāsura — and asked what they desired. They asked for immortality. Brahma declined: immortality is beyond even the creator's authority to grant. So the three brothers, with the particular cunning that the tradition consistently attributes to asuras who understand theological negotiation, asked for something more precisely constructed. The Three Forts and the Impossible Condition The boon they requested was architectural. Three cities — one…