In China, QR codes are everywhere, used to pay for seemingly every single thing all day long, adding up to an estimated $1.65 trillion in transactions in 2016 alone. Not so much in the U.S., where, apart from some experimental use by Snap and Facebook, people barely notice the QR codes around them — except, now, in youth voter registration.

What's going on: In their most recent popularization in the U.S., QRs are front and center in the anti-gun violence movement from March for Our Lives, launched by students at Marjory Stoneman Douglas High in Parkland, Fla.

After the February massacre at the school, in which a gunman killed 17 students and teachers, Jammal Lemy, 20, a local t-shirt designer and former Stoneman student, was asked by movement leaders to design merchandise to help fund their national tour.

• The students decided to model their merchandise after that sold by the National Rifle Association, which rallies its supporters using patriotism. "We said, 'We are patriotic too' — that Americans have the right to dwell in public spaces peacefully and safely," Lemy tells Axios.
• The students' main objective is registering youth voters for the November midterms.
• These two factors came together late one night, when, after numerous rejections of his design ideas, Lemy envisioned an American flag in which a QR code took the place of the stars.

The idea was that 38 states allow online registration, so if you scan the t-shirt's QR — which Lemy thought would be an irresistible impulse — you would be taken instantly to a voter registration page.

• The impact: The Parkland students say some 10,000 people have registered using the t-shirts. "It's being politically active with swag," Lemy said.