Hi Suzanne-
Basically, Miranda got it right. A Nine-patch block has 9 squares in a 3 by 3 grid, a Four-patch has 4 squares in a 2 by 2 grid.
As Patrice said, most pieced blocks can be divided into a grid of squares, the simplest ones are just a square of fabric in each space of the grid. The more complex can have more than one piece in them.
Are you totally confused now? :lol: LOL Hope not!