/^?(a)$?/, F
/^?(b)$?/, F
/^?(o)$?/, T
---
/^?(a)$?/, F
/^?(b)$?/, F
/^?(o)$?/, T
---
/^?(o)$?/, T
/^?(b)$?/, F
/^?(a)$?/, F
---
/^?(o)$?/, T
/^?(b)$?/, F
/^?(a)$?/, F
---
/^?(a)$?/, F
/^?(o)$?/, T
/^?(b)$?/, F