Tibetan letter "A" for dream yoga.
Tibetan A is a sacred symbol that is used in tibetan practices of yoga dream. It is essential to concentrate on that symbol for improvement of awareness in lucid dreams.
The images below are drawn from tibetan script. I've made to use as a desktop background. I can make it in any resolution you wish absolutely for free. Feel free to ask.
Learn more about dream yoga in that magnificent work:
Tenzin Wangyal Rinpoche - The Tibetan Yogas of Dream And Sleep
Best wishes for you.