This is very clever. E-mart the largest retailer in South Korea increased sales 25% during lunchtime using a shadow QR Code. The QR Code was only scannable between 12pm and 1pm when the sun was in a position to cast the correct shape shadow. The QR Code resolved to a ‘Sunny Sale’ mobile homepage with special offers, coupons and a download for the ecommerce app. The campaign (video below) was conceived and managed by Cheil Worldwide who were also responsible for the virtual grocery store in Hangangjin subway station in Seoul.