"Nail," said Dad. Joy reached into her sack.
"Nail!" she said, handing him one.
Dad pounded it into a board with his hammer.
"Good job!" said Joy.
Joy and her dad had been busy all morning.
They had moved Grandpa's wood up to the elm trees.
Then they bought more wooden boards and posts at the lumberyard.
Dad put two posts in the ground and built a frame for the tree house floor.
When he was finished, he looked at Joy with a frown.
"Partner," he said, "we have a problem."
"What's wrong?" asked Joy with surprise.
"See this wood we bought for the floor?" said Dad, pointing at a pile of 12 boards.
"They are two and a half meters long."
Joy looked at the boards and then looked up at the frame Dad had built.
She tilted her head and narrowed her eyes.
Then she smiled.
"Those boards look too long."
"You've got a good set of eyes!" said Dad.
"The frame is two meters long, so we need to shorten each board by half a meter."
Dad and Joy knelt by one board.
"Hold this tape measure at the end of the board," Dad said, handing her the measure.
Then he pulled the tape along the edge.
"That's 25 centimeters," said Joy.
Dad pulled the tape some more.
"And that's 50!"
"Now I mark it with a pencil," explained Dad as he drew a black line.
"That's where we will cut the board."
"Should we measure and mark all of them?" asked Joy.
"Yes," said Dad.
"Then I'll cut them down to the right size.
And you know what?
We can take the leftover wood to the recycling center."
"Somebody else will be able to use it," said Joy.
"Just like we used Grandpa's wood."
By late afternoon Dad had finished nailing the tree house floor to the frame.
He and Joy sat on the back end of the truck and looked up at their work.
"What's next?" asked Joy.
"Let's recycle that extra wood.
We might find a few things we need too," said Dad.
They got in the truck and drove down the hill to the road.
When they reached the center, Joy hopped out of the truck.
She liked looking up at the mountains of crushed cardboard and smashed soda cans.
She saw Mr. Ramirez, Carlos' father.
He was in charge of sorting all the metal—brass, tin, iron, steel, and copper.
"Hello, Mr. Ramirez," called Joy.
"Dad and I are building a tree house!
Do you have anything we can use?"
"Well, let's see," said Mr. Ramirez.
"Do you need a bucket?"
"We might," replied Joy. "Thanks!"
Dad was looking in a cardboard box.
"Here are some old hooks," he said.
"The kids can hang stuff on those," said Mr. Ramirez.
Joy dropped the hooks into her bucket.
"What's this?" asked Joy. "A wheel?"
"It's a special kind of wheel," said Mr. Ramirez.
"It's called a pulley.
You use it with a rope to help lift something."
Joy turned to her dad.
"Do we need one?"
"Take it," he said. "We can use it."
"Let's take this pole too," said Joy.
"It might be good for something."
Then Dad found some sheets of tin leaning against a wall.
"Our tree house roof!" cried Joy.
And that wasn't all.
They also found a small window frame and an old door.
They piled everything in the back of the truck and drove home.