Why QR code poems cause conflict in Philly's Old City

For almost two years now, artist Judy Breslin has been placing hundreds of poems on buildings across Philadelphia. There's no paper, no paint, just stamp-sized stickers with a jumble of black and white blocks. When these QR codes are scanned with a smartphone app, they conjure a few lines of text on a screen. They may be small, but Breslin says the stickers are placed almost always without permission. They dot storefront windows, parking meters, newspaper boxes.