Fun fact: through the years, Royal Dutch Shell's logo has changed quite a bit. It started as a depiction of a mussel shell, the current scallop shell logo came as recent as 1971.

"the pecten symbol currently in use worldwide was designed in 1971 by loewy. the design and testing process completed by loewy's firm took more than four years. one of the tests involved hanging various prototype pectens on poles where they could be viewed by drivers passing on a nearby british motorway. drivers were later contacted for their opinions on the prototypes."

http://www.designboom.com/portrait/loewy.html