The kuṇḍa — fire-pit shapes
The fire is kindled in a kuṇḍa (pit) or on a raised altar (vedi). Ritual texts describe many shapes — square, circular, half-moon, triangular, lotus-shaped and others — each linked to particular directions and purposes in large ceremonies.
For home use, the most common is a small square copper or iron havan-kuṇḍa shaped like an inverted stepped pyramid, placed on bricks or a sand tray. The square is considered suitable for most rites.
Square kuṇḍa for home
Homam — the sacred fire offering · Ask a Jyotishi your own question