What is Hyung's Tree of Life tattoo?

Hyung's Tree of Life tattoo is a symbol of the gradual change in Young's perception of hyung over the course of their relationship and in the years that followed. The tattoo is related to hyung's vaguely explained philosophy, as he declares, "It contains the principle of the universe I once studied" (85). Young finds this somewhat charming initially, but like all of hyung's charms, it wears off considerably as Young discovers that his boyfriend is a controlling person and a self-hating gay man. Toward the end of their relationship, Young observes, "The Tree of Life on his back seemed to wither" (106). This indicates that Young is no longer seeing hyung with rose-colored glasses.