I made this for my kid's carnival-costume.
The three parts (Base Disk, Flash, Ring) can be printed separately in fitting colors.
The base disk is sewn on to a red longsleeve or the like. Then, the flash and the outer ring are attached to it and secured with a drop of glue. The threads/stiches are then fully covered up and invisible.
The original Flash-logo is somewhat pointy so I added a second version with slightly rounded tips, which might be more suitable for smaller children.
The FreeCAD source-file (0.20) is icluded.
The author marked this model as their own original creation.