reference to ox knuckle-joint bones used in divination practices by sangomas, Southern African traditional healers. They somewhat resemble these bones. The second is a reference to ox or lamb knuckle bones used by African children at play. The name was attached to the objects when Kruger's father, Joe Kruger, who also worked in the harbour, came upon his son and others playing with small models of the objects and asked him Wat speel julle met die dolos? (English: What are you playing at with the dolos?). There is a very ancient game called knucklebones, a modern version of which uses playing pieces as shown in the adjacent photograph. The similarity between these and dolos is beyond question. See also – jetties were reinforced using dolosse in the 1980s maintaining the entrance at one of the world's most treacherous harbor entrances Notes and references Eastern Cape Dispatch, 28 June 1999 Martin Creamer's Engineering News, 16 February 2001 South African Financial Mail, 3 December 2004 External links POSIBLOC™ system for placement aid of concrete blocks Civil engineering Coastal construction Coastal engineering Wave-dissipating concrete blocks South African inventions