HIS BODY IS COMPOSED OF FLESH AND BLOOD
Atthinam nagaram katam mansa lohita lepanam
Yattha jara ca maccu ca mano makkho ca ohito.
Of bones is (this) city made, plastered with flesh and blood. Herein are stored decay, death, conceit, and detraction. 
Princess Janapada Kalyani was the daughter of Gotami, the foster mother of Gotama the Buddha. Because she was very beautiful, she was also known as Rupananda. She was engaged to be married to Prince Nanda, a cousin of the Buddha. One day she pondered, 'My elder brother who could have become a Universal Monarch has renounced the world to become a holy man. He is now a Buddha. Rahula, the son of my elder brother, and also my husband to be, Prince Nanda have become bhikkhus. My mother, Gotami, has become a bhikkhuni, and I am all alone here!' So saying, she became a bhikkhuni herself. Thus, she had become a bhikkhuni not out of conviction but only because of her attachment to her family.
Rupananda had heard from others that the Buddha often talked about the impermanency of the body. So she thought that he would talk disparagingly about her good looks if he should see her; and thus thinking, she kept away from the Buddha. But other bhikkhunis, coming back from the monastery, kept talking in praise of the Buddha until one day, she decided to accompany them to the monastery.
The Buddha saw her and reflected, 'A thorn can be taken out with a thorn. Rupananda is very attached to her body and is very proud of her beauty. Therefore I must take the pride and attachment out of her through beauty.' So, with his supernormal power, he caused a vision of a very beautiful lady about sixteen years of age to be seated near him. This young girl was visible only to Rupananda. When she saw the girl, she realised that compared to that girl, she herself was just like an old, ugly crow next to a beautiful white swan. Rupananda liked her very much. Then, she looked again and was surprised to find that the girl had grown to the age of about twenty. Again and again, she looked at the figure beside the Buddha and each time she noticed that the girl had grown older and older. Thus, the girl turned into a grown-up lady, then into a middle-aged lady, an old lady and finally a very old lady. Rupananda also noticed that with the arising of each new image, the old image disappeared, and she came to realise that there was a continuous process of change and decay in the body. With the coming of this realisation, her attachment to the body diminished. Meanwhile, the figure had turned into an old, decrepit lady who could no longer control her bodily functions and was rolling on the ground. Finally, she died, her body got bloated, pus and maggots came out of the body.
Having seen all these, Rupananda pondered, 'This young girl has grown old and decrepit and died in this very place before my own eyes. In the same way, my body will also grow old and decay. It will be subjected to disease and I will also die.' Thus, she came to perceive the true nature of the body. Responding to further guidance from the Buddha, Rupananda attained Arahanthood.