Wall-e has been learning 2on2off on the plank in the backyard -- woohoo, I'm staying on track with our winter goals :) I used shaping to train the position, which worked well for him. Right now he can run across the flat plank and stop in 2o2o while barely collecting himself (which is what I want, because it means that it'll help him ease into a running contact eventually). Pretty often, though, he either stops short and stops in a 4-on position, or doesn't stop at all, so he probably doesn't understand the position as well as I thought. Back to basics -- this morning, I began backchaining the 2o2o position again, jumping onto the side of the plank from the ground, which a jump standard on either side to help him. He did really good, and I was already seeing improvement by the end of the 3-minute-or-so session.