aa_allow: /* innermost frame allows a */

aa_block: /* innermost frame denies a */

ab_allow: /* innermost frame allows a */

ab_block: /* innermost frame denies a */

aba_allow: /* innermost frame allows b,a */

aba_block: /* innermost frame denies b */

aba2_block: /* innermost frame denies a */

abb_allow: /* innermost frame allows b,a */

abb_block: /* innermost frame denies b */

abb2_block: /* innermost frame denies a */