A back three uses three centre-backs instead of two. How 3-4-3 and 3-4-2-1 systems work, why back fours turn into back threes in possession, and what it costs.
The 3-5-2 plays three centre-backs, two wing-backs, three central midfielders and two strikers. How it attacks and defends, and why the wing-backs decide it.
The 4-4-2 sets up four defenders, four midfielders and two strikers in three flat lines. Why it defends so well, where it is outnumbered, and who uses it.
The 4-2-3-1 uses four defenders, two holding midfielders, three attacking midfielders and one striker. How the double pivot and the number ten make it work.
The 4-3-3 lines up four defenders, three midfielders and three forwards. How the single pivot, the two number eights and the wingers work, and where it breaks.