A padi kolam, also called kalyana or kanya kolam is a line kolam drawn using parallel lines which cross over at right angles or diagonally. They may start from a dot or a square and form basic structures such a square, a circle, a cross with diagonals, a swastika or two superimposed triangles. Padi kolam are not simple artistic variations. With their straight lines, they grace the doorsteps of Shaivite Iyer Brahmin houses.
These patterns are more abstract and celebrate the upstrokes and downstrokes of Hindu philosophical speculations. Like a yantra or a mandala, negative powers are prevented from entering by the very presence of four stylized gates facing the cardinal directions. The center of a padi kolam is never left blank and we find one or several dots, diagonal lines, the sun and the moon, a pentagon or a star hexagon.
The central square of the padi kolam bears a resemblance to the layout of Tamil temples, as well as sacred temple ponds. The parallel lines demarcating the contours of the kolam evoke the numerous enclosures and pyramid-like gates surrounding the sanctum. It also symbolises the steps of the sacred temple pond.
To enlarge a padi kolam, we add a series of parallels lines from which new lines join the preceding ones. Around the design, lotuses, conches or other ornamental motives complete the kolam.

Free translation from my book « Voyage dans l’imaginaire Indien, Kôlam, dessins éphémères des femmes tamoules » Editions Geuthner.

Panguni festival in Mylapore, Chennai. The women draw in front of Kapaleeswarar temple before the arrival of the chariots carrying the deities. The temple is dedicated to Shiva who is revered in the canonical work Tevaram, written by Tamil poets known as the Nayanars.