Ptolemy also produced another solution to the tuning problem. The diffculty withPythagorean tuning is that, while most of the the fourths and all of the fifths are perfect,the intervals are inconveniently large. For example, no note between C and F will form aconsonance with either note. However, the evidence of the senses points to a peculiarity.Consider an interval spanning three notes (and two whole tones), say C-E. This would bean interval of a third. Since it corresponds to the inelegant ratio 81 : 64, thirds are con-sidered dissonant in Pythagorean music theory. The problem is that if the notes are playedmelodically (one after the other), they seem to be consonant; it is only when they are playedsimultaneously that their dissonance is obvious.