coign

By many a dern and painful perch

Of Pericles the careful search

By the four opposing coigns

Which the world together joins,

Is made with all due diligence

In both the orthogonal and clinographic projections the light rays joining the eye and crystal coigns (solid angles, corners at which three or more edges meet) are all parallel

South of the North American coign we have again a pair of east - west mountain chains