cars, when a plate of regular size cannot be applied at the available space. The characters on the licence plate, as well as the narrow rim framing it, are black on a white background. In standard size they are high, and wide for letters or wide for digits. The smaller plates bear characters of height and width, respectively. In the current system, introduced in 1956, they consist of an area code of one, two or three letters, followed by an identifier sequence of one or two letters and one to four digits. The total quantity of characters on the plate must not exceed eight. Identifiers consisting of one letter with one- or two-digit numbers are often reserved for motorcycle use since there is less space for plates on these vehicles, especially before the reduction of plate size to 180 × 200 mm and 220 × 200 mm in 2011. Typeface Modern German plates use a typeface called (, tamper-hindering script). It is designed so that the letter P cannot be altered to look exactly like an R, and vice versa; nor can the F or the L be forged to equal an E, etc. Another feature is the equal width of all characters, different from the old DIN 1451 script which had been in use since the introduction of the current system, in 1956. FE-Schrift can be read by OCR software for automatic number plate recognition more easily than DIN 1451. The present style was introduced in 1994 and became mandatory in 2000, so the number of licence plates issued in the old style has become very rare. As with many plates for countries within the European Union, a blue strip on the left shows a shortened country code in white text (D for = Germany) and the Flag of Europe (12 golden stars forming a circle on a blue background). Material Traditionally, German licence plates are made of aluminium sheet, with embossed characters rising above background level. Over the years, however, various other materials have been used, albeit to a small extent only. Since 2013, a new style of plates made of plastic is allowed. They are said to be less sensitive to mechanical damage and to cause less CO2 emission in their production, but are more expensive. Number plates are retroflective, but must not be mirroring, concealed or soiled, nor may they be covered by glass, foil or