I find it very amusing that there are people on this site refuting what BMW's own historian is saying about the roundel origins. Yes, the armchair historian knows more than the obviously well-educated and well-versed BMW employee. I saw a special on I think the History Channel a couple years ago about BMW and in it there was a long-time BMW employee that commented about the evolution of the roundel. He noted that it didn't actually evolve from a propellor and that many people, BMW employees included, don't know that.
"The Camaro's V6 makes so much horsepower because them horses are trying as hard as they can to run the fuck away from that ugly ass car." -Golden3ye