It is generally accepted to see Lily. the painter, as a deputy for Virginia Woolf, the writer. It is only a little way from seeing her picture as the novel itself.
To the Lighthouse is divided into three parts: Part I. "The Window," Part II, "Time Passes," and Part III, "The Lighthouse." Lily sees Mrs. Ramsay, the heroine in Part I, through "tunnel" of time, and paints her portrait in Part III. Cam, as a deputy for Virginia Woolf, is reconciled as a daughter with her father, Mr. Ramsay, when the boat reaches the Lighthouse in the even number chapters in Part III. Lily sees them going away across the sea, and paints a portrait of Mr. Ramsay in the odd number chapters in Part III. She completes their portraits when she has achieved some distance from them. In order to combine the portraits and make a unified picture, she draws a line in the centre. The line signifies the distance, the "tunnel," from Lily to Mrs. Ramsay, and to Mr. Ramsay. The line connects the odd number chapters in Part III with Part I, and with the even number chapters in Part III. The picture becomes H-shaped, a shape which Virginia Woolf conceived her novel to be, in a trompe-1'oeit style.
In To the Lighthouse Woolf wrote her parents' portraits and the process of writing at the same time. The discovery and the improvement of what she calls a "tunnelling process" made her Tower-Bridge-shaped elegy possible.