Coats of arms in Germany, the Nordic countries, Estonia, Latvia, the Czech lands and northern Switzerland generally change very little over time. Marks of difference are very rare in this tradition, as are heraldic furs. One of the most striking characteristics of German-Nordic heraldry is the treatment of the crest. Often, the same design is repeated in the shield and the crest. The use of multiple crests is also common. The crest is rarely used separately as in British heraldry, but can sometimes serve as a mark of difference between different branches of a family. Torse is optional. Heraldic courtoisie is observed: that is, charges in a composite shield (or two shields displayed together) usually turn to face the centre.