Large staples found on corrugated cardboard boxes have folded legs. The first imported roofing material was corrugated iron sheeting. Another material which is sometimes used is corrugated cardboard. Adult flies lay clusters of eggs in the edges of corrugated cardboard or corrugated plastic. More common are small seatings or little tables made from corrugated cardboard. On the underside is a layer of corrugated steel sheets. Thus, it makes a more uniform substitute for corrugated cardboard. Ailerons were of a tapered design with corrugated aluminum covering. Such designs include corrugated slabs and ribbed slabs. This was corrugated cardboard as we know it today. Military and weather-resistant grades of corrugated fiberboard are available. This is a brick building with a low pitched gable roof sheeted with corrugated iron. Project 3.2 involved structural tests of corrugated steel arches. The steel door to the blockhouse was sheltered by another piece of corrugated iron. Cushioning is usually inside a shipping container such as a corrugated box.