My partner and I got this image at one point:
And I immediately add:
(this is blind to him, other than how many I've added).
My partner hasn't added anything.
Finally he adds one, but it's not a match. A few seconds later and he passes, and it asks me if I want to pass. "WTF?" I think. Okay, I pass. He isn't getting it.
At the end of the game it shows you your partner's failed guesses. What did he guess?