The ter'angreal is made up of three gray, metal rings that stand vertically in a circle and are joined at the middle.
The rings are used as a rite of passage for a woman becoming a Wise One apprentice. When she enters any of the rings, she experiences countless possibilities of her future based on every decision she might make. Most women cannot remember the majority of these experiences.
Some women do not emerge from the rings, likely from not being able to handle what they see.