A note from Knitting-and.com about the yarn and needle requirements:

Odd balls and scraps of yarn in your chosen colours. Needles to suit the thickness of your yarn. I worked mine in DK wool on size 3.75mm needles. Amount of yarn depends on the size you want your finished afghan to be as it is worked in squares that are then pieced together.

This pattern appears in Mason-Dixon Knitting as the Mitered Square Blanket.