Blocking

Blocking is the deliberate act of reducing something's accessibility or a player's mobility.

You can block buildings in order to protect them or you can block players in order to mess with their minds. You can even block yourself if you find your existence meaningless. Blocking is one of the basic acts of exerting influence on others. Clever use of blocking and cards can give you an extended appropriation of a planet (useful if you want a private mine).

For blocking we often use walls and gates because they are cheap for their size and resistant. If there are multiple layers of walls, it can takes some time to free the blocked space. Planet blocking elements (like forests and mountains) are not destructible, use them to enhance the blocking effect.

Be aware that some acts of blocking are forbidden tactics in the present state of the game, don't do them.