> Here is an Alex story that I posted on another forum:
>
> I had a conversation with Alex, age 6, who is a big fan of any kind
> > of game. I told him about the scooter games played at the
> > Southeastern Cushman Club meets, and he particularly liked the one
> > where you put a ball into a pipe and then ride the scooter down to
> > the other end and try to catch it when it comes out.* So he asked, "Can you bring that one up on my computer?" He's a modern kid.
> > Howard
>
> * Picture a rider over sixty and a scooter that is 40 or 50 years old. The pipe is about 20 feet long and slightly downhill.
>

Open trivia question:

You have a ball that will roll through a pipe from height H to some distant point on the ground, horizontal distance L away. What shape of pipe will get the ball to the ground the fastest?

Since L is nonzero, the pipe can't be completely vertical.

^v^:)^v^
FB