In patent 2,508,514, granted 23 May 1950, J. M. Hanert describes a significant revision to the PedalTone generation system. The bottom 12 tonewheels, heard only in the PedalClavier, are modified to produce a more complex waveform than the simple sine wave previously used in this octave. These tonewheels are round cut with two flat sides on opposites sides of the ToneWheel. This shape generates a "complex tone comprising a fundamental (f) and a series of odd harmonics of progressively decreasing amplitude, namely 1/3 (3f), 1/5 (5f), 1/7 (7f), 1/9 (9f), 1/11 (11f), etc." The resulting output from each of these first 12 tonewheels is very similar to the shape of a square wave.
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