What about a " Name that Morph " contest ?
Show a close up shot or two of a particular morph, and see who gets the right answer first.
Goodness knows we all have fun playing that game here. And by using fairly closeup shots, you would eliminate the instant wins.
Sure anybody can figure out the difference between say, a pied and a calico with full body shots, but get down just close enough, and is that patten a bee ? a clown ? Maybe it's a lesser ? Wait, it's a pinstripe! Isn't it ? You can see where I'm going with this.
Gale