On a room addition, I am doing a "corner window". I have framed a single opening that extends back from the corner of the room about 18" along BOTH of the walls that meet at the corner. It's open from about 3ft to 7ft above the floor. There is no sort of support or jack at the actual corner; I have done this with the assistance of a skilled professional carpenter, so everything is structurally sound (the headers that are cantilevered from the main part of each wall out 18" over the opening are designed properly). I will have two IGUs (custom-size pieces of insulated window glass) fabricated, each about 18" wide by 4ft tall, that will form the corner detail. The thing I can't figure out is what will happen where the two pieces of glass meet at the corner. I'm not too worried about structure, as each piece of glass will be firmly supported on the other 3 edges, nor am I much concerned about air leakage, as whatever I do will be caulked with something like silicon. But I am concerned about what will look best. The IGUs will be 3/4" thick, in order to have a 1/2" air space (for good thermal performance) and 3/16" tempered glass on the outer side (since the corner is so exposed to damage). So the spacer/seal bands along the edges will be visually significant. I can imagine three ways to do it. 1 - Just butt-joint one piece against the other. 2 - Have the two pieces meet on their inner corner (so the inner pieces of glass just touch) and caulk a 3/4 x 3/4" piece of trim in to square off the corner. 3 - Get what are known as "step glazed" IGUs, where the edge of the inner piece of glass is stepped back from the edge of the outer piece (some specified fraction of an inch along one side of each IGU); note this does not produce a smooth 45-degree bevel along the edge of the IGU, just a jagged approximation thereof. So I solicit thoughts on which of these options seems best, and possible additional strategies.