At the beginning of Sheila Heti’s new book, “Pure Colour,” God looks at a first-draft world he should get around to changing. The reader meets protagonist Mira, who bonds with a woman named Annie. Then Mira’s father dies, and his soul enters her; astonishingly, their combined selves become a leaf on a tree. Annie longs to bring Mira out of leaf form. Annie is what Mira calls a fixer. “Pure Colour” is a singular book that needs to be accepted rather than interpreted. Sheila Heti speaks about how she couldn’t think or write in the same way she did before the death of her own father.