Further remembering about myself:
Trataka (Sanskrit n. त्राटक Trāṭak: "look, gaze") is a yogic purification (a shatkarma) and a tantric method of meditation that involves staring at a single point such as a small object, black dot or candle flame.
Image source: https://commons.wikimedia.org/wiki/File:Candle_flame_01.jpg
