Two pence (British decimal coin) dots, a common feature on coins, known as beading. As with all new decimal currency, until 1984 the portrait of Queen Elizabeth II by Arnold Machin appeared on the obverse, in which the Queen wears the 'Girls of Great Britain and Ireland' Tiara. Between 1985 and 1997 the portrait by Raphael Maklouf was used, in which the Queen wears the George IV State Diadem. In 1992 the metal used in minting this coin was switched from bronze to copper-plated steel. From 1998 to 2015 the portrait by Ian Rank-Broadley was used, again featuring the tiara, with a signature-mark below the
Decimal decimal fractions were non-positional. However, counting rod fractions were positional. Qin Jiushao in his book Mathematical Treatise in Nine Sections (1247) denoted 0.96644 by J. Lennart Berggren notes that positional decimal fractions appear for the first time in a book by the Arab mathematician Abu'l-Hasan al-Uqlidisi written in the 10th century. The Jewish mathematician Immanuel Bonfils used decimal fractions around 1350, anticipating Simon Stevin, but did not develop any notation to represent them. The Persian mathematician Jamshīd al-Kāshī claimed to have discovered decimal fractions himself in the 15th century. Al Khwarizmi introduced fraction to Islamic countries in the early 9th