The final stage of quilting is to attach the top, batting, and backing together. This can be done in two ways. One way (quilting) is to sew elaborate patterns on it. The simpler but just as effective way (knotting) is to sew a thread through intervals and tie knots in it.
The symbolism of the knotting is the fact that Mrs. Wright killed her husband by tying (and knotting) a rope around her neck. simple, not elaborate, but just as effective.
In Trifles, John Wright is dead and the circumstances of his death are very suspicious, especially as he "died of a rope round his neck," says his wife without any display of emotion. Mr. Hale had approached the farm house wanting to talk to John about the possibility of installing a telephone line and it is he who notifies the police, as Mrs. Wright sits rocking in her chair, her apparent lack of any real awareness making Mr. Hale feel uncomfortable.
After Mrs. Wright has been taken to the courthouse, the men who come to the house to investigate the circumstances of the assumed murder are immediately judgmental and comment on Mrs. Wright's obvious lack of "the homemaking instinct." The women jump to her defense and remind the men how difficult it is to be a farmer's wife and also how unfriendly John Wright was.
As the women gather some things to take to Mrs. Wright, they notice the quilt that she has been "piecing" and Mrs. Hale wonders whether her intentions were "to quilt it or just knot it." The men overhear this conversation and mock the women's concerns because, while they investigate a murder, the women worry over "trifles." The county attorney even repeats the question and the women decide that she was most likely going to knot it. It is also significant that the presumption that Mrs. Wright would have intended to "knot" it is the last line of the play.
A quilt is a blanket and so symbolizes warmth, something that Mrs. Wright never got from her husband. In this era, quilting would also have been a social activity where women would meet and help each other to quilt whilst exchanging gossip and advice. The act of knotting the quilt is a considerably easier task in blanket-making (although both methods achieve a completed quilt) and it is therefore an important reference in the play because it emphasizes the theme of loneliness and isolation as Mrs. Wright has no social circle and is much a victim as she is a potential killer.