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Chord ID trains chord identification by ear. Chord ID has three answer modes: Functions (Roman numerals), Chords (C Maj, Dmin, etc.), Qualities (Maj, min, dim). Graduated exercises begin with the easy task of identifying only the I or V chords.

With this program, one can draw images to see the effect of gravitational lensing. You can easily test the effects of several parameters by changing them and redrawing the image.