(a) Suppose that the sensitivities of the receptors in the eye were not shaped like Gaussian bumps, but were instead triangular, the graph of the red receptor being an equilateral triangle with base between 600 nm, and 700 nm, the green having its base between 500 nm and 600 nm, and the blue having its base between 400 nm and 500 nm (all three equilateral triangles having the same heights). What would the CIE diagram look like? How many primaries would be needed for perfect color reproduction?

(b) Suppose instead that the domains overlapped so that red was defined on [500, 600], green on [450, 550], and blue on [400, 500]. What would the chromaticity diagram look like? How many primaries would be needed to faithfully reproduce every color percept?