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In C. S. Lewis's The Silver Chair, there is a chapter called, "The Hill of the Strange Trenches," in which the Narnian characters are in a land of giants, wandering around a hillside with seemingly meaningless trenches. In the next chapter, they make a discovery about the trenches:
The ledges which they had climbed down on the north side of the hill - and also, no doubt
the other ledges which they had climbed up on the south side - were the remaining steps of
giant stairs. To crown all, in large, dark lettering across the centre of the pavement,
ran the words UNDER ME...
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"What I don't quite understand," said Jill, "is how we didn't see the lettering? Or could
it have come there since last night. Could he - Aslan - have put it there in the night? I
had such a queer dream." And she told them all about it.
"Why, you chump!" said Scrubb. "We did see it. We got into the lettering. Don't you see?
We got into the letter E in ME. That was your sunk lane. We walked along the bottom stroke
of the E, due north - turned to our right along the upright - came to another turn to the
right - that's the middle stroke - and then went on to the top left-hand corner, or (if
you like) the north-eastern corner of the letter, and came back. Like the bally idiots we
are." He kicked the window seat savagely...