A special anniversary 50p celebrates the science behind the world’s first seven-sided coin

Introduced two years prior to decimalisation, the shape of the 50p heralded the revolution to come. Hugh Conway and his team drew upon their knowledge of precision engineering techniques to create the world’s first seven-sided coin. Even though it wasn’t circular, it still rolled smoothly thanks to its shape of constant width. As we continue our 50 years of the 50p celebrations, a special anniversary coin pays tribute to the science behind this radical design.