When I was a child, I had dreams about an almost inaccessible room in the family home. Then when I was 10, I went for a drafting Merit Badge in the Cub Scouts,

When I was a child, I had dreams about an almost inaccessible room in the family home. Then when I was 10, I went for a drafting Merit Badge in the Cub Scouts, and plotted the floor plan of our house. Assuming standard Euclidean Geometry, no, there isn't a hidden room. But now I keep reading about secret servants' passages in stately homes, hotels, and the like.