My dad worked overtime in the evening a fair bit. He'd often bring me when I was a young teen. The building was several stories tall with a huge open central core, just a flight of stairs on one end.

I'd go to the top floor, take a bunch of paper from the printer room and fold planes, and send them out into the central space. Go back, tweak the design or try something new, launch again.

Don't think I came up with any good designs, but I had a lot of fun trying various ideas.