If you like grumpy dogs, who walk with their heads low as if they are bored out of their minds, and do not wag their tail, but they shake their butts and as they are tufted it is like watching a ball of wool going back and forth, then there is Billy.
The above description has nothing to do with reality, but it is what you see when Billy passes by you. You see a fluffy white ball. The reality is that this ball is a dog that has not been properly socialized, and now it is just beginning to learn the world again.
And as he learns the world, he marks him on every walk, which may sound funny, but for a dog like him, marking on the walk shows that he is more confident than he seems.
Billy goes for slow and calm leash walks, with a bit more confidence each time, he has begun to timidly wag his tail to those he knows, lifting his head a little, and as soon as you approach him he takes one step back and two forwards, to come for a gentle petting.
Dogs like him are dogs that make little progress in the shelter, but they can make huge progress in a home, with proper instructions, and with patience.