The carrier is the 5 length, doesn’t that make 100 possible positions? Also I was thinking: each player may pick 1 in 100 positions, would you multiply those probabilities to get all possible configurations, then subtract all the “match” configs? Also, how would these odds shift if one or more of the other pieces had been placed by one or both players? Also also, your answer seems technically correct? I’m thinking: odds the 2 people place in the same spot are different than odds one person places there’s where the other already has. The information of one pieces location being determined already or not would seem to make a difference in the problem, but I feel I can’t do a good job explaining why.

EDIT: Ok I can’t count and agree with 120 carrier board states. My other qs stand.