Over the next few weeks I used the tools that I'd brought from the ship to build a fence around the cave. Inside the fence I left some space for all my things and to walk around. The fence was made of pieces of wood about a meter and a half high. I used the tools to make the top of the fence very sharp so that it would be difficult to climb over. Instead of making an entrance for me to walk through, I decided to use a ladder. Every time I climbed over the fence, I pulled the ladder after me so nobody could climb it and surprise me when I was sleeping.