Via carrots are orange and ReadyMade, here’s how to fold a t-shirt:

1. Lay shirt face-up on a smooth surface, long side facing you, with the neck on your left. With the edge of your hand, draw an imaginary line from shoulder to hem on the far side. Along this line, pinch the shirt with your left hand at the shoulder and with your right at the middle of the chest.
2. Fold the shoulder over, crossing left hand over right, to meet the hem along this line. Now pinch the hem and shoulder together with your left fingers.
3. Lift the shirt and uncross your hands, pulling the shirt taut. Give it a shake.
4. Lay the shirt down sleeve first, then the body face-up on top to finish. (For long sleeves, lay the shirt fully facedown in Step 4, then fold the sleeves in neatly before the final fold.)

Topo­log­i­cal­ly, it reminds me of the Duvet Burrito Roll Trick.