Most devices use three line segments, but devices made by some japanese companies such as sharp and casio, as well as in the koreas and taiwan, 7 is written with four line segments because in those countries, 7 is written with a hook on the left, as ① in the following illustration. The seven colors of the rainbow. Most calculators use three line segments, but in some brands of calculators, 7 is written with four line segments.
Generally open 24 hours a day. The pythagoreans called the number 7 “the septad” The number 7 is often considered lucky, and it has a definite mystique, perhaps because it is a prime number—that is, it cannot be obtained by multiplying two smaller numbers together.
Seven contains the number three of the heavens and soul with the number four of the earth and body
