This base is designed for the players who want to farm in th level 4. It is wise to stay in the 800 trophy range.
The air defense is placed outside the village, although the air defense is a much needed defense at higher town hall levels it is not at th level 4, attackers usually don’t have healers (available at th level 6). The only air unit that can be used are balloons but these are rarely used in this range.
The town hall is placed outside the walls so attackers can take it down easy. That way you will get an 11 hour shield to protect your resources. You can also place your town hall in a corner to maximize this effect.
The collectors and other buildings that don’t defend are placed outside the walls, be sure to collect the resources in the collectors often.
The mortar is the center of this defense in this th4 far layout, it can attack all sides and will do maximum splash damage.
The cannons and archer towers are each placed between their own walls, this way it will take the attacker a lot of time to destroy them all.
Because this is a farm base your storages are also in the middle to protect the resources.