A few years ago I got a lego portrait for christmas, I had lots of 1x1 lego bricks to spare once I had finished building it so decided it would be a fun project to build a QR code with them.
This is my lego portrait
The first challenge was finding a backboard big enough to build the QR code on, in the end I had to buy one along with a few more 1x1 plates because I wasn't sure if I would had enough.
The next challenge was learning about QR codes so that I could design and build one. For this I found a QR code generator online entered my text and started building. I got around half way through and realised that every time I wanted to change my message I would have to rebuild it. This is when I came across the idea of a dynamic QR code which takes you to a website that you can edit, I set mine up to be a rickroll but with a lego Rick Astley (Brick Astley).
I learnt about how QR codes work (see picture below). I have also managed to rickroll (an internet meme) many people. I also built a wooden frame so I can hang it on my wall.