These markings, often painted on the forehead of
Hindu devotees are often made from the ash of
incense burnt as offerings in front of deities.
These lines painted on the horizontal, represent
devotees of Shiva, while on the vertical, Vishnu.
The red spot is of course the Bindi and is often painted
on by a high priest, representing the feminine aspect
of the individual.
I really find all the symbolism of the Hindu religion so
fascinating and also quite beautiful.