Upgrading QR Codes

Riley Lark outlines the infinite layers of abstraction between a QR code and a trivial task like classroom voting and offers an upgrade:

If I wanted students to vote as they entered or exited the classroom, for example, I’d consider a piece of paper or the whiteboard with a few markers laid out. The process for voting is “pick up this marker and scrape it across the board in a check mark shape.”

About 
I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.