Can you find out if we fold this open cube in the Centre, what will be the resulting figure?

An old man had three sons. He was dying and wanted to leave all his property with his wisest son. So he calls all three of them gives them an equal amount of money and asks them to buy something from that money that can fill their living room.

The first son bought straw but due to shortage of money, he was not able to fill the entire room. The second son bought sticks, but again they were not enough to fill the room. But the third son bought two things that filled the room completely.

Can you find out what did he buy?