Magic Roundabout (Hemel Hempstead) Magic Roundabout (Hemel Hempstead) The "Magic Roundabout" in Hemel Hempstead, Hertfordshire, England, is the familiar name given to the Plough roundabout. The familiar name comes from the children's television programme, and is also used for a similar junction in Swindon and the M40 junction in Denham. The official name relates to a former public house, called "The Plough Inn", which was between the junction of what is now Selden Hill and St Albans Road. It has also been known as the Moor End Roundabout as it is adjacent to the part of Boxmoor nearest the town. Before Hemel Hempstead became
Magic circle (mathematics) Magic circle (mathematics) Magic circles were invented by the Song dynasty (960–1279) Chinese mathematician Yang Hui (c. 1238–1298). It is the arrangement of natural numbers on circles where the sum of the numbers on each circle and the sum of numbers on diameter are identical. One of his magic circles was constructed from 33 natural numbers from 1 to 33 arranged on four concentric circles, with 9 at the center. Yang Hui's magic circle series was published in his "Xugu Zhaiqi Suanfa"《續古摘奇算法》 (Sequel to Excerpts of Mathematical Wonders) of 1275. His magic circle series includes: magic 5 circles in square,