Experiment proposed by Michelson and Morley in 1887 sending two orthogonal rays of light and measuring the speed difference predicted by classical Galilean transformations. The measured speed was the same in both directions — a surprising 'bug' in reality that triggered ad-hoc patches (luminiferous-ether hypothesis) until Einstein reframed the problem. Used by Rząsa as a parable for how scientists respond to unexpected behavior: formulate hypotheses, design experiments, and publish results.