Chalk produce, and thus widely used in the developing world, calcium-based chalk can be made where the crumbling particles are larger and thus produce less dust, and is marketed as "dustless chalk". Colored chalks, pastel chalks, and sidewalk chalk (shaped into larger sticks and often colored), used to draw on sidewalks, streets, and driveways, are primarily made of gypsum. Chalk is a source of quicklime by thermal decomposition, or slaked lime following quenching of quicklime with water. In southeast England, deneholes are a notable example of ancient chalk pits. Such bell pits may also mark the sites of ancient flint mines,
Pick-up sticks Pick-up sticks Pick-up sticks or pick-a-stick is a game of physical and mental skill in which a bundle of "sticks", between 8 and 20 centimeters long, are dropped as a loose bunch onto a table top, jumbling into a random pile. Each player in turn tries to remove a stick from the pile without disturbing any of the others. The game is known by several names including jackstraws (or jack straws), spellicans, and spillikins, and appears in a line of a nursery rhyme: "...five, six, pick-up sticks!" The sticks may be made of almost any material, such as ivory, bone,