The fabric can&#x27;t always be rotated 90 degrees. Some T-shirts body portion is made from tubes of fabric. The ones with seams on the sides have the possiblity, but that highly depends on the weave of the t-shirt material itself. The material is knit in a way that is stretchy, and turning the pattern pieces (the only logical way to turn the fabric 90 degrees) can make the shirt not stretch the right directions when worn and&#x2F;or force changes in the garment itself.