Ripstop Nylon: Doubled Threads Woven in Every 5 to 8 mm, Both Ways

Ripstop is cloth with a grid of stronger threads woven in every 5 to 8 mm, both ways (Wikipedia). A small tear runs only as far as the next line of the grid. In the Army's parachute nylon (US 3,032,072, 1962) the rip-stop threads go in as doubled pairs, warp and weft, with ordinary threads between. The picture: ripstop fabric, the grid of doubled threads showing (Wikimedia Commons).