Travel game: walls

This is a fun travel game for 2-4 persons. It is easy to carry and leight-weight.
Purpose is to get your pawn to the opposite site, while blocking your opponent reaching your side (or with 3-4 playes to reach their other side)

rules
1- You must either make a step or place a wall, you can't do both nor skip your turn
2- It is not allowed to completely block a pawns path to the other side, a path must be available
3-You can not have 2 pawns on the same place or jump over one. It may be that