My lame but kinda cool idea of the day is a flexible whistle, made out of something along the lines of a garden hose. I’m thinking you could just wiggle it a little to get a vibrato.
I posted my cool idea the other day on the green board..
It’s a D whistle, with a G# instead of G, so I could play mason’s apron and Jenny’s Chickens without having to learn any new fingerings 
I recommend clear flexible plastic tubing rather than garden hose.
Yep. Tastes so-o-o much better. And you can study the flow of condensation.
…and also the growth of fantastic mildews
but then you wouldn’t get that nice garden hosey smell. There is just such an air of Je ne sais quoi about that
That is a cool idea! Daniel Bingamon makes whistles with alternate scales; he might be willing to do it.
It’s a D whistle, with a G# instead of G, so I could play mason’s apron and Jenny’s Chickens without having to learn any new fingerings
Along the same lines why not have both holes and a slide so one can be covered when not in use? An F hole would be handy too. 
Even less technical could use blue tak to close an unwanted hole.
Brian
Like this one?
I’m sure I saw this in a thread last year sometime…