The BMW logo looks roughly like this:

     _____
   /       \
  /   -+-   \
 /  /  |  \  \
 | |---+---| |
 \  \  |  /  /
  \   -+-   /
   \_______/


The outer ring is black, while the segments of the circle inside are alternating between blue and white. This is supposed to be a stylized image of an airplane's propeller; in their early days, BMW made mainly engines for airplanes. Also, white and blue are the traditional colors of Bavaria.