I scrapped both of my color changing decks, and have been reworking my sponge ball routine.
I've always loved sponge balls, but justification (as you said) is difficult. I use them as a learning/explination tool, something to keep your mind occupied while I tell you about something boring(and usually not true...yay sleight of hand).
This is basically what I have, I've been toying with the idea and don't have anything written up yet, nor is it audience tested yet. Another week of tinkering and handling changes and I'll probably have a formal write up...or a completely new idea.
Let's get into some psychology, specifically what you see and what you think you see. Sometimes what you see isn't real, and what seems real isn't there. I'll explain with a visual aid.
(reach into the air and hold imaginary sponge ball)
What do you see? *nothing*
(Reach with other hand and produce first red sponge ball)
And now what do you see? *small jolt of surprise, and they say a little red ball*
Right, and it's different than my right hand... *they say yes, looking towards right hand...now holding a second red sponge ball*
-it's different people, say it's still different...there are two in the right hand!- I love a good inner dialog, I won't post all of it here though.
[moving on]
So if I take what you see in my right hand and put it in your hand
(put one sponge ball in their hand)
and keep this one in my hand
(close hand around single sponge ball)
it appears that I have one and you have one. *agreement*
and it's true
(open hands to reveal nothings changed)
but what if I were to take this one
(take sponge ball from left with right, still having third ball hidden)
And switch it with this one
(clearly take the one from their hand and put two into specs hand ditching own sponge ball from left to right hand)
Now we can see the difference between what you see, or what you thought you saw, and what is real.
(open empty hand, point with right hand and they reveal two oh my god!)
(after a moment of reflection)
I'll show you again, only a little different, maybe you can keep up if I only use two hands, instead of three. (motion my two hands and no longer include theirs)
(take the sponge balls back...'one' in each hand)
If I put this one in my pocket (pull 'empty' hand) and close my hand around this one (around two) Then what you think you saw was one being put away and one being held.
What really happened was one was put away, but not in my pocket. I put it away in my other hand. (reveal two in one hand)
But if I was to put one into my left hand (show putting one into hand, put none) and this one in my pocket (put both red ones in pocket) then how many are in my hand.
At this point you have two answers...some will say one, hopefully a lot will say two due to repetition.
If one, 'Are you sure?'...hope to get a two, ask other spectators and find someone willing to say two.
Yes, two. But I wonder if you've really seen what's going on so far. Would you mind saying what color they are?
*confused look, 'red?'*
No, you thought you saw red ones, I only deal with *insert color of choice* ones (open hand revealing different colored sponge balls).
(I have some yellow ones but plan on getting a different set)
It's something I've been toying with, the subtleties aren't their yet, this is the first 'formal' writeup, I'll re-read after work and edit it a bit.
Fun stuff so far, glad to see you back Morgician.