Diaphragm (optics) curved blades improve the roundness of the iris opening. In a photograph, the number of blades that the iris diaphragm has can be guessed by counting the number of diffraction spikes converging from a light source or bright reflection. For an odd number of blades, there are twice as many spikes as there are blades. In case of an even number of blades, the two spikes per blade will overlap each other, so the number of spikes visible will be the number of blades in the diaphragm used. This is most apparent in pictures taken in the dark with small
Sigurd Snake-in-the-Eye Snake-in-the-eye features prominently in History Channel's historical drama television series "Vikings" played by David Lindström. Sigurd Snake-in-the-Eye Sigurd Snake-in-the-eye (Old Norse: Sigurðr ormr í auga) was a Viking warrior in the middle of the 9th Century. He was supposedly one of the sons of the legendary Viking Ragnar Lothbrok. "Snake-in-the-eye" as part of Sigurd's name denoted a physical characteristic. He was born with a mark in his eye, described as the image of the Ouroboros (a snake biting its own tail). The snake mark had been prophesied by his mother Aslaug, the daughter of the Valkyrie Brynhildr. As a boy,