Here we are, trying our own version of one of the toys from 'fun-with-dogs', the German site devoted to enhancing human-canine interaction. (If you click on the British flag you will get the main page in English.)
And I'm just gob-smacked by the wonderful games on the page devoted to a competition to find the most creative toy. You don't need to read German, because the photos speak for themselves.
I think I love the last one on the page best of all. An old hand-puppet has become a friend that only opens his mouth to reveal a wonderful treat when the dog offers an interesting behaviour. The reward is for creativity, for thinking up - and offering - a new behaviour.