A few years ago, I got to visit the Louvre in Paris and one of the sections that fascinated me was the Russian Icon Collection. The icon painters would fast for many days inside dark caves in contemplation. At some point, they would actually “see” the face of a saint in the total darkness (“with their mind’s eye”) and would proceed to paint it using gold leaves. Andrei Tarkovsky has a masterful film about one such painter, Andrei Rublev.
I believe many traditional Tibetan and Bhutanese paintings are depictions of spiritual experiences that people actually experienced. There are many techniques of exploring the mind and many of this art seem to be providing guidelines or maps for seekers to follow.
Kind of like a Lonely Planet Guide to your mind!