This is a QR code that you or anyone else can scan that will take you to YouTube and Rick roll you. I made this QR code small enough to where I can have it on my phone case however you can have it be whatever size you like. The filament I used is black PLA and it works great as it is. You still need white as the background color in order for it to scan properly. I also made height differences as well just so it doesn't confuse anyone when they try to color in the patterns.