Technically, a diagonal is a line having an oblique or slanted direction [syn: aslant, aslope, slanted, slanting, sloped, sloping], or perhaps, a line joining two opposite corners of a straight-sided object.
For our purposes, a diagonal is a line, or even a suggestion of a line, sloping or slanting between the corners of real, or suggested straight-or-not-so-straight-sided shapes, or similar suggested shapes within.
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