2 / 2 \ (1 + a) *\1 + a - a/
/ 2 \ 1 + a*\1 + a *(1 + a)/
/ ___\ / ___\ | 1 I*\/ 3 | | 1 I*\/ 3 | (a + 1)*|a + - - + -------|*|a + - - - -------| \ 2 2 / \ 2 2 /