Explanatory notes
… H, I, T, capital omega, Z and U (including channels), obtuse, acute and right (L) angles. The corners may be square … or shipbuilding beams). Angles, shapes and sections are usually produced by hot‑rolling, hot‑drawing, hot‑extrusion … and sections (e.g., girders, beams, pillars and joists) are used in the construction of bridges, buildings, ships, etc.; …