After fan-fiction started coming out about Red and Blue, from Alola, I thought it would be fun to cosplay the infamous trainer. In addition to his signature hat, yellow backpack, and shirt, Red has a black bracer.

I created this bracer to expand when I put my hand through it. The bracer expands with the help of elastic, although any other band could be used if you don't want the bracer to expand.

Red's bracer measures approximately 3 inches in diameter by 1.5 inches tall. It can be scaled up pretty reliably if you want the segments to be larger.

To assemble the bracer, print eight of these segments and string them with .75 inch elastic. At the very end, you should be able to overlap the two ends of elastic, and sew them together. The excess elastic can then be cut and the entire band tucked into one of the many loops.