G.K. Chesterton: The Secret Garden of Paradox and Philosophy

The garden was large and elaborate,
and there were many exits from the house into the garden.
But there was no exit from the garden
into the world outside;
all-round it ran a tall, smooth, unscalable wall
with special spikes at the top;
no bad garden, perhaps,
for a man to reflect
in whom some hundred criminals had
sworn to kill.