Bi-metallic coin dated 2006 (minted at Noida). Since 1996, Canada has also produced bi-metallic $2 coins (nicknamed "toonies"). Great Britain has issued a bi-metallic 2-pound coin since 1997; and Singapore has issued a bi-metallic 1-dollar coin since 2013. The first ever tri-metallic circulating coins were 20-francs coins introduced in France and Monaco in 1992. These were similar to the corresponding bi-metallic 10-francs coins, but had two rings instead of one. As well as circulating coins, where they are generally restricted to high-denomination coins, bi-metallic coins are often used in commemorative issues, often made of precious metals. For example, the only bi-metallic coin
Trillion dollar coin Treasury in 1996. Laurence Tribe, a constitutional law professor at Harvard Law School, said the legal basis of the trillion dollar coin is sound and that the coin could not be challenged in court as no one would have standing to do so. Professor Jonathan H. Adler of the Case Western Reserve University School of Law has said that he believes the legality of the trillion dollar coin to be dubious. The idea for the Treasury Department to mint a coin and send it to the Federal Reserve in order to pay off the debt was first popularized by Populist