First step was mapping out the triangles with the brush tool in photoshop.

After the triangles were mapped out in photoshop, I took the image into Illustrator and used the pen tool to trace over the triangles.

With the triangles all traced out, it was time to fill them in. Once that was completed. I brought the image back into photoshop to do a little editing. I deleted the background and added an orange gradient to compliment the blue hoodie. Cropped the image a little as well and and brought down the opacity on the vector smart object to reveal some of the texture in the original photo.