kayin, wartilykirri

When someone sees a branch growing in a boomerang shape in a suitable tree, such as supplejack or mulga, he might chop off the branch and shape it with an axe and adze into a kayin (curved boomerang) or wartilykirri (hooked 'number seven' boomerang). He might rub it with red ochre or carve grooves into the surface. The grooves increase the boomerang's speed and stability as it travels through the air, in much the same way as the dimples on a golf-ball. Boomerangs can be used for hunting, fighting, fire-making, trading and, in matched pairs, as percussion instruments. Although one of the most well-known symbols of Aboriginal Australia, the returning boomerang was generally only used in south-eastern Australia.