Angela Wexler is standing on a hassock because she is having her wedding dress altered. The increased height causes the bottom of her dress to be raised a couple of feet so that the dressmaker can more easily access it. As Mrs. Baumbauch, with pins in her mouth, crawls around on the floor adjusting the dress's hem, Angel herself stands "as still and blank-faced pretty as a store-window dummy," looking out the window at the lake across the way.
Angela is engaged to be married to Dr. Denton Deere. She is not as excited about the upcoming union as is her mother, who considers Dr. Deere to be a worthy match. Grace Wexler is a controlling woman, and she treats Angela like a fragile, precious doll with no mind of her own. Mrs. Wexler is supervising the fitting from the comfort of a beige velvet couch, and when Angela cries out while pivoting in a slow quarter turn according to Mrs. Baumbach's instructions, the overprotective mother assumes that the dressmaker has pricked her daughter and cautions her to be more careful. Angela, however, has not been pricked. She had uttered the exclamation because she had noticed smoke coming from the Westing house chimney, and was surprised, because the house was supposed to be empty (Chapter 3).
she was getting her wedding dress ready