This is a carnival mask to be worn on an arm, so you can be Falcon 9 🚀. This work is based on this model of SpaceX Grid fin created by Tim O'Brien.
I modified the STL model from Printables in OpenSCAD to have the round part which wraps round the arm with a groove to hold the rubber band.
The mask consists of two grid fins which were both printed in two parts on Prusa Mini and glued together.