I am making my second quilt... an amish style quilt. Each block consists of a center square...behind center square is another square turned on its side like a diamond (4 triangles), and behind the "diamond" is another square (4 triangles) in same position as the first center square. Sorry, my description leaves something to be desired. Anyway, every time I measure, measure, measure then cut, sew triangles and squares together, iron and it seems that each block is slightly different in size. What is my inexperience missing?