Illustrating the Michelson-Morley experiment
  Considering that the rays in the Michelson-Morley interferometer perform the radar detection of its mirrors, we use a relativistic diagram that displays, at a convenient scale, their location and the path of the rays. This approach convinces us that the rays that come from the two arms interfere with zero phase difference without using the usual ingredient, length contraction. 
Bernhard Rothenstein, Stefan Popescu, and George J. Spix