The notice at the entrance to the national park is a small masterpiece of plain writing, and it fits on one board.
«You may camp only where both conditions below hold. Pitch your tent at least fifty metres from the lake, and stay within three hundred metres of a marked path.»
The first rule protects the water. Tents pitched at the water's edge wear away the bank and frighten the birds that nest in the reeds. The second rule protects the campers: a rescue team looking for someone in fog can search a strip beside a path far faster than a whole valley.
Together they carve out a band of ground — not too close to the lake, not too far from the path — and the warden's map has it shaded in green.
Last August she turned away two groups on the same evening. The first had pitched 45 metres from the shore: a beautiful spot, and 5 metres inside the prohibition. The second was 65 metres from the water, which was fine, but 380 metres from the nearest path, which was not. Each group had obeyed one rule and broken the other.
A site 65 metres from the lake and 240 metres from a path breaks neither, and that is the whole test. The green ground on the map is not a suggestion — it is simply every point where both sentences are true at once.