Four-patch and nine-patch blocks are basic units for building thousands of patterns. As the names Indicate, four-patch blocks are constructed from four separate units, nine-patch from nine. They can be combined into double-four patch blocks, sometimes referred to as sixteen-patch blocks, or into a double nine-patch, which contains nine discrete compound blocks. The blocks’ primary units can be plain squares or rectangles, or combinations of shapes such as four triangles joined to make a square. The plethora of patterns breeds an almost infinite choice of design possibilities, and fascinating and unexpected secondary patterns frequently spring to life when blocks are joined together to make a quilt.
