For this shirt design, you will need tape scissors, and some way to keep the shirt together during working (I used 9x clothespins)
Laying the shirt flat with the seems as the edges, tape one line down the shirt. Leave a slight gap from the edge.
Go all the way accross with your tape, leaving a slight gap from the opposite edge as well. At the end, you may need to lift and retape the last few lines to make them appear a bit more uniform. It does not need to be exact.
Cut off the bottom seem first, try to keep some uniformity to it.
Clothespin every few stripes to keep the shirt aligned during cutting.
Weight down the top of the shirt with something to keep it from moving on you, and start cutting inbetween the tape lines you made. Not each line will be cutting the front and back of the shirt, making two strips each. The sides seem pieces will be one piece unfurled, which is why you left a little space to start.
Remove all your tape.
Grab each piece one by one. Note that because of taking the picture, I was only using one hand. you should use your other hand to hold the strip at the base of where you cut it.
Give it a few strong pulls to thin it out.
Notice the difference between pulled and unpulled.
All done! There is a ton of different patterns you can put into this type of design with knots, weaves, flowers, and so forth.