This takes places the summer before Fred's last year at Hogwarts.
His mum had invited his grandparents over for lunch one weekend. It was mid-afternoon when a polite knock sounded on his door.
"Come in," he called out. Writing down the last measurement, he abandoned his pencil and turned to find Granddad Arthur hesitating in his doorway.
"Hey, there. Come in, come in," Fred urged.
"Hope I'm not disturbing. I can go away if this is a bad time," Arthur offered kindly.
Fred loved his grandfather. He was the nicest, most non-intrusive Weasley in the family. And Fred appreciated how he took an interest in all of his grandchildren yet managed to make them all feel special. It was a testament to raising so many children.
"No, no. It's fine, really."
"Your father's gone out for a bit and Molly and Angelina are discussing some recipe. I thought maybe I'd bother you for a bit," Arthur said with a smile, slowly walking around Fred's room, taking stock of the new books on his shelves. As had been his grandson's habit for the past years, they were all about architecture.
Arthur enjoyed Fred's mind's mechanics, the love for building things, constantly trying to improve his technique. It was fairly similar to his own passion for re-inventing Muggle things and Arthur secretly thought with some pleasure that Fred had gotten that through his father from him.
"No bother, Granddad."
Fred smiled benevolently at his paternal grandfather. Arthur was always curious and interested in anything new. It hid his advanced age well, the childlike glee for discovering some new invention or idea. Fred had always enjoyed sharing his thoughts with him.
Eventually, Arthur finished his perusal of the bookcase and made his way to Fred's worktable. A powerful lamp shone brightly on a big sheet of paper laden with Fred's ingenious designs.
"This looks interesting. What are you working on now, Freddie?" Arthur asked, coming behind his grandson and placing a hand on his shoulder as he leaned over to better inspect the diagram. "Is it a hotel of some sort?"
The blueprint was nearly complete. Fred simply enjoyed constantly tweaking it, adding or erasing something as a new idea occurred to him or he learned something new and useful that he believed he could use.
"Actually, it's a house."
"Pretty big house."
"Well – this is more of a fantasy project of mine, Granddad." Fred felt just the slightest bit awkward about revealing this to anyone so he stopped with the clarifications there. But as always, his Granddad Arthur never failed to put his observant spirit into gear and suss things out.
Eyes narrowed a bit, Arthur carefully considered what he was looking at.
"For us? The Weasley family?" he asked eventually.
Fred smiled, pleased with his grandfather's astuteness.
"Yep. You know, if for some reason we all decided to move in together. Which is unlikely but I dunno. The idea flew into my mind one night and well, I had to sketch it out. You know how it is."
Arthur did indeed. Once some sort of invention waltzed through his imagination, he was nearly obsessed with it and had to get it out somehow, despite Molly's vehement threats to level his shed if he didn't stay away from tinkering with magic and Muggle artefacts.
"This is pretty brilliant, Freddie," he complimented and then allowed his nephew to present his little project to him. Fred explained about room dimensions, and intelligent space-savers, and all sorts of designs from all over the world, colour schemes fitted to each member, and the best materials to use, durable and affordable, and leaving open the possibility for expansion seeing as how the Weasley children would one day have families of their own.
Arthur appreciated his grandson's inventiveness and his eyes sparkled with admiration and pride as Fred prattled on about the blueprint.
"This is a truly wonderful plan, Fred. Have you shown anyone else this?"
Fred shrugged.
"No, not really. Like I said, it's a fantasy project. The family wouldn't want to all live together, be lumped like that. Dad and his brothers all get along but to actually live together? It'd drive them all bonkers, you know that."
Arthur chuckled. He knew perfectly well that his sons and daughter all had very distinguishing personalities that sometimes clashed.
"You're quite right. Still, this is pure genius." Fred's cheeks flamed up at that. That was high praise from his granddad. "Who knows? Maybe we could one day re-design the Burrow like this. Or have this as a vacation home somewhere. You should show this to your dad, your uncles. They might take on the idea."
"You reckon they wouldn't laugh at it?"
"Nah. I think they'd love it. They might laugh about the lot of them sharing living quarters again but that's something else. And if any of them do, you just send 'em to me and I'll set them straight."
Fred looked at his grandfather with absolute adoration. A peaceful man, Arthur always stood up for his loved ones.
"Granddad, you're the best!"
Very fluffy, I know. But the Weasley family is quite large and this is how I see Arthur as a grandfather. Besides, creating Fred 2.0's personality is wonderful, like colouring in the line art J.K. Rowling gave us.
Disclaimer: I do not own any of the characters.