wriggly tin (taken from UK military slang),
pailing (in Caribbean English), corrugated sheet metal (in North America) and occasionally abbreviated CGI) is a building material
composed of sheets of hot-dip galvanized mild steel, cold-rolled to produce a linear corrugated pattern in them. The corrugations
increase the bending strength of the sheet in the direction perpendicular to the corrugations, but not parallel to them. Normally
each sheet is manufactured longer in its strong direction.