Euro coins edge of the €2 coin also protects it from counterfeiting. Euro coins were designed in cooperation with organisations representing blind persons, and as a result they incorporate many features allowing them to be distinguished by touch alone. In addition, their visual appearance is designed to make them easy to tell apart for persons who cannot read the inscriptions on the coins. The coins increase in size and weight with value. Of the eight denominations of euro coins, the three lowest denominations are small, resemble copper in colour and are quite thin and light. The next three denominations resemble gold in
Euro banknotes and in 2002 notes and coins began to circulate. It rapidly took over from the former national currencies and slowly expanded around the rest of the EU. In 2009, the Lisbon Treaty formalised the Euro's political authority, the Euro Group, alongside the European Central Bank. Slovenia joined the Eurozone in 2007, Cyprus and Malta in 2008, Slovakia in 2009, Estonia in 2011, Latvia in 2014 and Lithuania in 2015. There are seven different denominations of the euro banknotes: €5, €10, €20, €50, €100, €200 and €500. Each has a distinctive colour and size. The designs for each of them have