Dicephalic parapagus twins Hensel, born in Minnesota in 1990, are another instance of dicephalus parapagus twins who grew up. They were born with two functional arms, plus a vestigial third arm, which was surgically removed. Each twin has her own complete head, heart and spine, and controls one arm and one leg. They learned to walk around the same age as average children, went on to attend school, learn to drive, play sports, and completed courses at college. Twin girls conjoined like the Tocci brothers, with four arms and two legs altogether, were born in Turkey in 2000. As with the Toccis and
There are known knowns management and strategic planning circles. Known unknowns refers to "risks you are aware of, such as cancelled flights..." Unknown unknowns are risks that come from situations that are so unexpected that they would not be considered. "For example, prior to the invention of the personal computer, manufacturers of typewriters probably didn't foresee the risks to their business". Contemporary usage is largely consistent with the earliest known usages. For example, the term was used in evidence given to the British Columbia Royal Commission of Inquiry into Uranium Mining in 1979: The term also appeared in a 1982 "New Yorker" article on