A1 | A1

--- 'out ---> A0 | A1
--- 'out ---> A1 | A0

A0 | A1

--- in ---> A1 | A1
--- 'out ---> BufferA

A1 | A0

--- in ---> A1 | A1
--- 'out ---> BufferA

BufferA

--- in ---> A0 | A1
--- in ---> A1 | A0