A coin brick, based on the reference, is a brick used to form a quoin, which is an external corner of a building. The reference specifies that the material commonly used for forming quoins can be stones or bricks.
Here's a breakdown:
- Quoin: The external corner or angle of a building.
- Coin (Brick): A brick used in the construction of a quoin. According to the reference, if the brick (coin) is arranged so that its width is parallel to the face of the wall, it's known as a coin.
