This tetrad has the special property that it is the smallest collection of notes which can create the feeling of "completely representing" a particular regular temperament in a "standard" way. However, it only works in even-numbered edxs, for it contains sqrt(x), and it becomes a very weakly "complete" representation of a regular temperament as L:s grows large.
Golden bi-equal tetrad: major 0-phi-phi+1-2*phi+1, minor 0-1-phi+1-phi+2/(2*phi+2)edx
in edo: major 0-370.82-600-970.82 cents, minor 0-229.18-600-829.18 cents
Natural logarithm bi-equal tetrad: major 0-e-e+1-2e+1, minor 0-1-e+1-e+2/(2e+2)edx
in edo: major 0-438.635.82-600-1038.635 cents, minor 0-162.365-600-762.365 cents
Bi-equal wheel tetrad: major 0-pi-pi+1-tau+1, minor 0-1-pi+1-pi+2/(2*tau+2)edx
in edo: major 0-455.128-600-1055.128 cents, minor 0-144.872-600-744.872 cents