In a normal (1s improper) contra, you start with your partner across from
you and your neighbour next to you. Anyone outside the minor set is a new
neighbour / shadow / something else.
In a Becket formation, you start with your partner next to you. Who's
opposite you - your neighbour or your opposite? If it's your opposite,
who's your neighbour? Is it the person next to you who isn't your partner?
(I have seen it used this way.)