What rangoli is
Rangoli is a pattern made on the floor, traditionally at the doorway, as a welcome and as an auspicious mark during festivals. It is most associated with Diwali but is made at weddings, at Onam and Pongal under other names, and on ordinary mornings in many households.
The patterns are geometric, floral, or figurative, worked freehand from a grid of dots or laid over a stencil. Material varies by region and occasion — rice flour, flower petals, coloured powder — and coloured sand is the version that holds a sharp edge and a strong colour for longest.