Magenta is a purplish red color evoked by lights with less power in yellowish-green wavelengths than in blue and red wavelengths (complements of magenta have wavelength 500–530 nm). In light experiments, magenta can be produced by removing the lime-green wavelengths from white light. It is an extra-spectral color, meaning it cannot be generated by a single wavelength of light, being a mixture of red and blue wavelengths. The name magenta comes from the dye magenta, commonly called fuchsine, discovered shortly after the 1859 Battle of Magenta near Magenta, Italy.
Check out this experiment: http://www.greatreality.com/Color2Color.htm
[related HN thread: http://news.ycombinator.com/item?id=459970]
Magenta is definitely a color. What the author meant to say is that magenta can't be a single frequency -- but that title wouldn't have gotten as many clicks.
So in colour there is no sharp dividing line between a 'chord' and a 'note'. Some 'chords' look like 'notes' and some 'notes' look like 'chords'. Magenta is interesting because it's always a 'chord'.
[severely edited, trying to fix bad writing]
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GR : COLOR=1 : PLOT 20,20
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