Avalokiteshvara, the Buddha of Compassion, is often depicted in Tibetan tradition as having eleven (11) heads. Three stacks of three, facing forward and left and right, another one on top, and another, different, one atop that.
Here's the reason: He reflected on the fact that no matter how many creatures he helped, there would always be more. He reflected on it till his head exploded.
Just thought you'd like to know.
But his spritual father Amitabha Buddha took the ten pieces and fashioned ten heads, then gave him one of his own to keep the whole thing straight.
However, when Avalokiteshvara got to China, he had only one head, and he's called Guanyin, and he's female.
I am not making any of this up.
Sometimes you can learn a lot by just watching. One of the things I've watched is the new Tibet exhibit at the Asian Art Museum here.