I have the pattern in my Carol Doak's pattern file and it can be PP. You will have four units. Pattern is also called "lady in the lake". Two long units that will be six of the half-square triangles, one unit that will be 4 half-square triangles and one large unit that will be the center half-square triand and the 4 half-square triangles. If this makes any senses at all !
If you do the hour glass center variation you will have five units since the hour-glass is two units.