Several C-flute single-wall regular slotted cubical corrugated boxes with dimensions from 12X12X12 to 22X22X22 were modified at the four corners with corner offsets from 1 inch to 8 inches to form diagonal (or “two-angle”) corners. They were conditioned at the standard test condition of 73 F  and 50% RH. The optimum corner offset varied from 22% of box dimension to 26% with an average of 24%. The maximum compression strength increased from the regular corner configuration from 23% to 62%, with an average of 44%. In addition, an average of 14% saving on material at optimum corner offset.