If someone flies overhead in a nightly flight, a lighted design of India will reveal underneath on Diwali night.
For the Hindus, from tarpan to Diwali, amabasya to amabasya (new moon), a month of tryst with departed souls ends. In tarpan, in the wee hours of morning, the thirsty souls of forefathers are given water. In the Bengali month of Kartik, akashprodip, the sky-lamps are lighted on roof-tops. These lamps are supposed to give light to the dark paths to guide the spirits to their designated places in heaven.
This akashprodip climaxes in Diwali. The day before Diwali is Bhootchoturdoshi. On that day, fourteen lamps are lighted at the places, where the man or men, once lived in the house, frequented in the near or long or long long past. The front and back door, corn-storage, base of the bel tree, ghat of the pond, latrine or bathroom (decades back the latters are built far away from the house) are the places where the lamps(prodip) are kept a-lighting for the night. The spirits can re-visit the places with lights to show them the way to; the belief goes.
Life is kept in touch with the dead; present with the past. Life is living with the dead; an acceptance that life includes death, not excludes it.