Bristol Food For Free. Food for Free ~ Silk Map. SILK MAP 2nd World War Pilots used silk maps Silk maps are extremely durable, do not disintegrate in water, are not damaged by repeated folding and unfolding or by being screwed up into a ball, and are silent to unfold and use. They are easy to conceal, can be sewn into the lining of a jacket or the hem of an undergarment. The silk map can be used as scarfs, picnic cloth and carrying aids. The material and history of the silk map suits the metaphors and functionality of the food for free map. Food for free silk map is under construction.