He thought about that often.
One evening, while reviewing drawings at the kitchen table, he asked his daughter a question.
“Why do you want to reach the big tree so much?”
She looked up from her crayons.
“Because there's a hollow in it.”
“A hollow?”
She nodded.
“My friends say squirrels hide things there.”
He smiled.
“You want to look for squirrels?”
“No.”
He raised an eyebrow.
She continued.
“I want to hide treasure.”
He laughed.
“What treasure?”
She held up a small purple stone she'd found near the sidewalk.
“This.”
He studied the stone.
It was ordinary, smooth, and probably worth nothing.
But the girl held it as though it were a diamond.
He nodded seriously.
“Very valuable.”
She grinned.
“And maybe I can leave a note for somebody to find.”
The father watched her.
Then asked, “What would the note say?”
She thought for a moment.
Then smiled.
“Keep going. There's more to see.”
He stared at her.
For some reason, the words affected him.
He reached for his notebook.
Then wrote them down.
Keep going. There's more to see.
He didn't know why he wanted to preserve the sentence.
He simply knew it belonged somewhere important.
The project continued through autumn.
They obtained preliminary components.
Produced drawings.
Examined commercially available equipment options.
Consulted professionals.
And began building non-load-bearing prototypes and test fixtures to evaluate certain ideas without putting the girl at risk.
The father's workshop filled with sketches.
He labeled folders.
Kept measurements.
Recorded the advice they received.
And organized every document so another person could understand the project even if he wasn't present.
His wife teased him about the growing collection.
“Do you really need six different notebooks?”
He smiled.
“Seven. I haven't finished the last one.”
She shook her head.
Then kissed his cheek.
“You and your machines.”
He wrapped an arm around her waist.
“You married me.”
“I was young.”
He laughed.
She smiled.
Then looked toward the drawings.
“You really think we can do this?”
He considered the question.
“I think we can find the right people and keep trying until we have a safe answer.”
His wife nodded.
She liked that answer better than a promise of perfection.
The project was still unfinished when winter arrived.
The father began working longer hours at the manufacturing plant.