A man is in a prison cell. It's a very comfortable prison – it's warm and dry, he's well fed, and he has plenty of books, writing paper, and writing implements. The furniture is comfortable, and he has a nice writing desk. The guards disturb him once every twenty minutes all day, so he can't concentrate on his reading or writing as he'd like, but even so – a comfortable prison.
His cell has one window. Outside is a dingy street, grey and dirty. It's often deserted apart from rats and mangy dogs running everywhere. When there is anyone there, they're filthy, dressed in rags, shouting at each other and fighting. The weather is foul every day – raining and cold, with a biting wind driving the rain into everyone's rags. It seems to have been like that for years.
Then one morning they move him to a different cell, looking out onto fields, trees, a pretty river, and a lovely waterfall. The same day, the weather brightens dramatically – it's sunny and warm. There are children laughing and playing in the fields, and lambs skipping about. The wind is just a gentle breeze – just enough to make the leaves of the trees rustle, which he can hear in the gaps in the children's laughter.
Conditions inside his cell are same as they were in the other cell.
His desire to escape from his prison was very weak before – imagine how it's changed!
In the morning he wakes up, and finds the second cell was a dream anyway. Does he still want to escape from his prison? Or does he want to escape back into the dream?
Or is he dreaming now, and was the second cell reality?