In Susan Glaspell's playTriflesthe discovery of the stitching plays an enormous role: it is a significant piece of evidence that helps to look deeper insider the mind of Minnie Wright.
Mrs. Hale is the only character in the play who has met Minnie Wright at a more personal level than anyone else. Granted, Mrs. Hale had not seen Minnie in years by the time the crime is committed. One thing is for sure: Minnie Wright has changed after her marriage, spiraling down from what seems to be a pattern of psychological and maybe even physical abuse from her husband.
When Mrs. Hale and Mrs. Peters find a piece of quilting with which Minnie had been working, they were surprised to see how, at first, the piece seems to be quite organized and put-together. Yet, abruptly, the stitching seems erratic and out of place.
Mrs. Peters, look at this one. Here, this is the one she was working on, and look at the sewing! All the rest of it has been so nice and even. And look at this! It's all over the place! Why, it looks as if she didn't know what she was about!
This is indicative of Minnie's state of mind; a woman so stressed and nervous that she cannot even devote herself to stitching. Perhaps stitching, under her state of mind, was her only comfort.
This specific instance helps the plot move forward because the question that Mrs. Hale poses to Mrs. Peters will be answered almost immediately with the discovery of the birdcage and the dead canary. The question asked by Mrs. Hale is:
What do you suppose she was so nervous about?
As Mrs. Peters tries to alleviate Mrs. Hale's suspicions with a semi evasive answer, she tries to detour the conversation and asks for paper and string to wrap the belongings that Minnie had asked to get to spend her night in jail, they come across the birdcage with the hanging hinge but no bird inside. After making conjectures about what could have happened, they find the dead canary whose neck had been wrung. This was eerily similar to the manner in which John Wright himself had been killed. This is when the two women realized that John Wright must have killed that bird just to spite Minnie. As a result, she must have snapped and killed John the same way. This is the ultimate conclusion of the two women.