Explain Alice Walker's own account of how The Color Purple was born?

The Color Purple was born on a walk Walker took with her sister in the woods. The two women were talking about a lovers triangle... people they both knew, and Walker's sister said, "And you know, one day The Wife asked the Other Woman for a pair of her drawers." It was at this moment that the story Walker had been writing in her head about two women who felt married to the same man came to fruition... she had her missing piece.