[Retric]

Coins don’t need to be tiny and round, just small, standardized mediums of exchange. There’s plenty of square coins: https://en.wikipedia.org/wiki/Coin#/media/File:Coin_of_the_B...

Larger denominations of precious metal backed currency like gold bricks can be considered coins, it’s rather arbitrary as to when something is to large to be considered a coin.

[HelloNurse]

Ancient Chinese quasi-functional spade and knife coins are an even more interesting departure from tiny round discs than square or oblong coins.