i
doublesinglesinglesingledouble
A
leftRepeatsinglesinglesinglesingle
singlesinglesinglesingledouble
B
double
singlesinglesingledouble
A
doublesinglesinglesinglesingle
singlesinglesinglesingledouble
B
double
singlesinglesinglesingle
single
singlesinglesinglesingle
1.
singlesinglesinglesinglerightRepeat
2.
double
singlesinglesinglesingle
singlesingledouble