This is one of the corners of the National Gallery of Art East Wing. It was designed by I.M. Pei and is configured more or less as two isosceles triangles aligned side by side pointing in opposite directions. This is the the pointy edge of one of the triangles. (See http://www.greatbuildings.com/buildings/East_Wing_National_Gallery.html)

This photo does a pretty good job of illustrating the sharpness of the angle, but one really needs to see and touch it in person to really appreciate it -- and they even let you do it. There's a place on the edge, about 1.5 m off the ground where the granite is polished smooth and shiny from all the sets of thumb-index fingers that have tested the sharpness of the edge. It's even neater inside -- although I'd hate to have a corner office in that apex.

PS - Minor (or no) curves and USM. Colorize w/Hue & Saturation. Frame