For this pattern you’ll need 8 squares each of 2 colours, one light and one dark. However, in keeping with the origins of the pattern – named for the thrifty stitchers of Depression-era America – the fabric doesn’t all need to be the same.
You can use up to 8 different fabrics per “colour”, but it helps to keep them all in the same tonal family.
(Extra credit: Listen to Lena Horne bemoan the weather in this 1943 classic)
Note: When your pieces are ready to be sewn together, make sure to trim them all to the same size to ensure they fit together correctly.