Strobogrammatic number Strobogrammatic number A strobogrammatic number is a number whose numeral is rotationally symmetric, so that it appears the same when rotated 180 degrees. In other words, the numeral looks the same right-side up and upside down (e.g., 69, 96, 1001). A strobogrammatic prime is a strobogrammatic number that is also a prime number, i.e., a number that is only divisible by one and itself (e.g., 11). It is a type of ambigram, words and numbers that retain their meaning when viewed from a different perspective, such as palindromes. When written using standard characters (ASCII), the numbers, 0, 1, 8 are
Tower Infinity of illumination are used to achieve different degrees of 'invisibility'. Because of the arrangement of the LED screens, the tower will appear invisible from only certain points distributed around the tower, ranging from near the tower to Seoul Bridge, about away. The screens will be so arranged that the tower will be visible from high altitudes, such as to airplanes and birds. Tower Infinity will be used primarily for entertainment and leisure purpose with a 4D theater, restaurants, a water park, landscaped gardens and the third-highest observation deck in the world. When the tower invisible cloak is turned off the