A father gathered his three sons and told them he would die soon and needed to decide which son would inherit his land. He gave them the following test.

“Go to the market and purchase something that is large enough to fill my bedroom, but small enough to fit in your pocket. Based on what you bring I will decide which of you is wisest.”

All three sons went to the market in search of something to satisfy their father’s demands. When they returned the father gathered them in his bedroom.

The first son put down pieces of cloth that he had bought and laid them end to end across the room, but it barely covered any of the floor.

The second son laid down hay but there was only enough to cover part of the floor.

The third son showed his father what he had purchased and the father announced, “You are truly the wisest and will inherit my land.”

What did the third son bring?

There are many English words that you can add an “s” to make it plural. But far fewer words become singular when you add an “s”. What are two examples of these much rarer words?