A symbol for the four evangelists in Gothic church architecture. More
common is in Group 26.
Dr. Timothy Leary, a professor at Harvard University during the 1960s, who was fired due to his experiments with LSD and his belief that this drug could be used for expanding awareness of subconscious structures and aspects of the world not perceived in a normal consciousness state, has propagated the sign as a symbol for the League for Spiritual Discovery.
This sign is also a native American symbol for peyote and is found commonly on Mesoamerican and Southern US tribal pottery and bags which are specifically made for carrying and preparing peyote for religious ceremonies. Some peyote cacti look like when seen from above.