He next wants to test whether smiley-face receipts might also work at self-checkout. If they do, that might not bode well for workers.

In Nirvana's copyright dispute with Marc Jacobs over its smiley-face logo, the band said Kurt Cobain created it. Now, their art director says he did.

He distributed 10 million smiley stickers for free, and soon the symbol’s joyful simplicity became a staple on car bumpers throughout the nation. As the smiley infiltrated mainstream culture ...