/ _____________ _____________\ / _____________ _____________\ / _____________ _____________\ / _____________ _____________\ | / ___ / ___ | | / ___ / ___ | | / ___ / ___ | | / ___ / ___ | / _____________\ / _____________\ | / b b*\/ 2 ___ / b b*\/ 2 | | / b b*\/ 2 ___ / b b*\/ 2 | | / b b*\/ 2 ___ / b b*\/ 2 | | / b b*\/ 2 ___ / b b*\/ 2 | | / ___ | | / ___ | | 3 / - + ------- I*\/ 3 *3 / - + ------- | | 3 / - + ------- I*\/ 3 *3 / - + ------- | | 3 / - - ------- I*\/ 3 *3 / - - ------- | | 3 / - - ------- I*\/ 3 *3 / - - ------- | | / b b*\/ 2 | | / b b*\/ 2 | | \/ 3 3 \/ 3 3 | | \/ 3 3 \/ 3 3 | | \/ 3 3 \/ 3 3 | | \/ 3 3 \/ 3 3 | |a - 3 / - + ------- |*|a - 3 / - - ------- |*|a + ------------------ + --------------------------|*|a + ------------------ - --------------------------|*|a + ------------------ + --------------------------|*|a + ------------------ - --------------------------| \ \/ 3 3 / \ \/ 3 3 / \ 2 2 / \ 2 2 / \ 2 2 / \ 2 2 /