Other common representations are on coins, postage and other stamps and banknotes, sometimes by no more than a mention or signature; and public places, streets, monuments and institutions such as schools are named for current or previous heads of state. In monarchies (e.g., Belgium) there can even be a practice to attribute the adjective "royal" on demand based on existence for a given number of years. However, such political techniques can also be used by leaders without the formal rank of head of state, even party - and other revolutionary leaders without formal state mandate.