In designing a fictional castle many things must be taken into consideration. The defenses must be made impregnable. There must be a supply of food to nourish the defenders and the peasants who come inside the walls for safety. A castle must also provide space for defensive weapons as well.
Our fictional castle was located on a precipice surrounded on three sides by the ocean. This left one road for attackers to use. To prevent this, we designed two walls with portcullises that ran the length of the Scottish isthmus that housed our keep. The first wall was composed of iron-reinforced wood; the second was composed of stone.
The castle itself had an inner wall and an outer wall surrounding it. Archers manned the outer, 30-foot, wall raining down fire arrows on our adversaries. Trebuchets and catapults were situated on the inner, 60-foot wall. These provided a defense for our castle during an attack or siege situation.
Located in the walls was a garden area that would provide our garrison with nourishment. There were also fields for grazing for goats, sheep, and cows that could also be eaten. In addition to this, holes, leading down to hidden caves, between the two walls provided us a route to get to the ocean to catch fish and collect other supplies.
Together, these three attributes contributed to the safety of our people. The blueprint provided an unassailable barrier between them and the enemy. Also, the fields and garden provided food for our people to survive a siege. And finally, the width of the walls allowed our garrison and our people to create their own defense.