Keeping to my right, I walk around the corner to meet a stone wall. Even when I lean back, I can't make out where it ends in the darkness above.

I turn back the way I came to see that the stones have moved; there is no corner to the path I had just walked. Instead, the wall extends in front of me, beyond what I can see.

After a deep breath, I resume walking.

I trip over a stray pebble and find a corner to my right.

I take it.

A dead end.

I retreat.

But there is no corner.