The cleverest son

Once there lived an old man who had three sons. When he grew old and ill he knew that he would soon die. He called all three sons into his room.

“There is no way I can divide the house and Farm to support all three of you. The one who proves himself the cleverest will inherit the house and Farm. There’s a coin on the table for each of you. The one who can buy something that will fill this room will inherit all I own”.

The eldest son took his coin, went straight to the marketplace in filled his wagon with straw. The second son thought a bit longer, then also went to the marketplace with his coin, where he bought sacks and sacks of feathers. The youngest son thought and then quickly went to the shop he bought two small things and put them into his pocket.

That night the father called them to show what they had bought. The oldest son spread his straw but it filled only one part of the room. The second son dumped his sacks of feathers but they filled only two quarters of the room. Then the youngest son smiled, pulled out two small things from his pocket and soon filled the room.

“Yes”, the father said, “you are indeed the cleverest and have filled my room when the others could not. You shall inherit my house and farm”.

What had the youngest son bought and how had he filled the room?