Rangoli is one of the most popular art forms in India. It is a form of sandpainting decoration that uses finely ground white powder and colours, and is used commonly outside homes in India. Rangoli can be wall art as well as floor art. The term rangoli is derived from words rang (colour) and aavalli ('coloured creepers' or 'row of colours'). The picture above is a Rangoli made at the entrances to one of the offices in Mumbai where the Puja of Goddess Durga was being held.
The motifs in traditional Rangoli are usually taken from Nature - peacocks, swans, mango, flowers, creepers, etc. The colours traditionally were derived from natural dyes - from barks of trees, leaves, indigo, etc. However, today, synthetic dyes are used in a range of bright colours. The materials used for Rangoli take on either a flat appearance, when a uniform monolayer of powders are sprinkled or a 3-D effect when different sized grains like cereals, pulses etc are used either in their natural colouring or tinted with natural dyes are used.
Info sourced from Wilipedia