The dog is supposed to lift the obstacles out of the narrow box in order to get the treats.
The box needs to be wide enough, so the dog will be able to eat the treats from the bottom of the box. And for the same reason the box can’t be too tall either. The box I’ve used, is about 15cm (5,9”) tall and 11cm (4,3”) wide.
Contrary to expectations, these games have been surprisingly difficult for Miki. Miki doesn’t usually lift the obstacles out, but instead tries to push them in the sides or just pushes the whole box over.
You can put all sorts of soft or rounded things as obstacles, like cups, balls, rubber toys, rope toys etc. And you can use any treats in these games. When I put cups facing down in the box, I hide the treats under the cups.
Depending on the obstacles, it usually takes Miki under a minute to get all the treats out.