the front facing down. cut off the collar of the shirt. cut a rounded rectangle from shoulder seam to shoulder seam approximately down to the bra-line. cut a second rounded rectangle from the bottom hem of the shirt to the first rectangle, leaving a 2-inch horizontal section in the middle. the result will be a h-shape open-back design on the back of the shirt. cut this middle section vertically through the center of the back. tie the cut ends back together to give the t-shirt a fitted appearance. 