Light up Marquee Letter M
thingiverse
You can check out the full assembly video here: https://youtu.be/Y8vLz1yCGUM. I'll mention now that the hole at the back is only just big enough for my 3V battery, so if you decide to wire it like I did, keep this in mind.
Download Model from thingiverse
With this file you will be able to print Light up Marquee Letter M with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Light up Marquee Letter M.