The spot Willie sought was that which would require the least labour and least material to make it into a room.
Before he heard the voice of Tibby, calling him to come to his porridge, he had fixed upon one; and in the following chapter I will tell you what led him to choose it.

All the time between morning and afternoon school, he spent in the same place; and when he came home in the evening, he was accompanied by Mr Spelman, who went with him straight to the ruins.
There they were a good while together; and when Willie at length came in, his mother saw that his face was more than usually radiant, and was certain he had some new scheme or other in his head..