power x' S x mult x' power x' x mult x' S x add0 x' mult x' x add0 x' S x + S 0 add0 x' x power x 0 S 0 mult x 0 0 add0 x 0 x + x S 0 S x + S 0 y S y power 2 + 2 S 1 0 0 add0 2 mult 2 INNERMOST