A B C D E F SS S1 [SS->S1] S1 S2 [S1->S2] S2 S3 S1 [S2->S3 and S2->S1] S3 ES S3 [S3->ES and S3->S3] ES
A valid for SS->S1 B valid for S1->S2 C valid for S2->S3 D valid for S3->ES E valid for S2->S1 F valid for S3->S3(loop)
A B C D E F SS S1 S1 S2 S2 S3 S1 S3 ES S3 ES
A valid for SS->S1 B valid for S1->S2 C valid for S2->S3 D valid for S3->ES E valid for S2->S1 F valid for S3->S3(loop)
A B C D E F SS S1 [SS->S1] S1 S2 [S1->S2] S2 S3 S1 [S2->S3 and S2->S1] S3 ES S3 [S3->ES and S3->S3] ES
A valid for SS->S1 B valid for S1->S2 C valid for S2->S3 D valid for S3->ES E valid for S2->S1 F valid for S3->S3(loop)