Rubber-Stamp Poetry

“Lion-Eating Poet in the Stone Den,” a poem by Zhao Yuanren, in English:

In a stone den was a poet Shi Shi, who loved to eat lions, and decided to eat ten.
He often went to the market to look for lions.
One day at ten o’clock, ten lions just arrived at the market.
At that time, Shi Shi just arrived at the market too.
Seeing those ten lions, he killed them with arrows.
He brought the corpses of the ten lions to the stone den.
The stone den was damp. He asked his servants to wipe it.
After the stone den was wiped, he tried to eat those ten lions.
When he ate, he realized that those ten lions were in fact ten stone lion corpses.
Try to explain this.

… and in Hanyu Pinyin:

Shishi shishi Shi Shi, shi shi, shi shi shi shi.
Shi shishi shi shi shi shi.
Shi shi, shi shi shi shi shi.
Shi shi, shi Shi Shi shi shi.
Shi shi shi shi shi, shi shi shi, shi shi shi shi shishi.
Shi shi shi shi shi shi, shi shishi.
Shishi shi, Shi shi shi shi shishi.
Shishi shi, Shi shi shi shi shi shi shi.
Shi shi, shi shi shi shi shi, shi shi shi shi shi.
Shi shi shi shi.