Necker Island (British Virgin Islands) would survive their castaway adventure for at least three weeks, but as McCullin later recounted, "because of our gathering weakness ... out of temper, and out of water, we hoisted the red flag and were taken off in the early hours of the fifteenth day". According to McCullin, there was nothing idyllic about the desert island: "The mosquitos and other insects were more venomous and persistent than any I had encountered in Vietnam or the Congo." Richard Branson's "Extreme Tech Challenge" has been hosted annually at Necker Island since 2015. Described as one of the largest technology competitions in the
Necker cube Necker cube The Necker cube is an optical illusion first published as a rhomboid in 1832 by Swiss crystallographer Louis Albert Necker. It is a simple wire-frame drawing of a cube with no visual cues as to its orientation, so it can be interpreted to have either the lower-left or the upper-right square as its front side. The Necker cube is an ambiguous line drawing. The effect is interesting because each part of the picture is ambiguous by itself, yet the human visual system picks an interpretation of each part that makes the whole consistent. The Necker cube is sometimes