More a one-off than a big idea, but an interesting way to make a time-specific promotion.

Having noticed that their sales dropped considerably during lunch hours, emart (self-proclaimed ‘the Walmart of Korea’) devised a QR code made of shadows that only works properly from 12 to 1pm.

During that time bracket, the QR code points to short promotions that end past noon and the online purchase gets delivered to the residential address of choice within the day.