Original: The two produced buttons as well as coffee mugs, t-shirts, bumper stickers and many other items emblazoned with the symbol and the phrase "Have a happy day" (devised by Gyula Bogar).
Simplified: The two used the "smiley face" on buttons as well to decorate coffee mugs, t-shirts, bumper stickers and many other things. They also used the phrase "Have a happy day" (which was the idea of Gyula Bogar).