Your pooch has once again blasted its way through the back-door screen, and you've had enough. You need a paw-proof grill. It's either that or get rid of the dog. You could go to a big-box hardware store, wander the aisles aimlessly and hope to catch the attention of some teenager pretending to work while chatting on his Bluetooth, only to find out that what you want is out of stock anyway. It's hard to imagine that the tiny hardware store tucked into a corner of the Tower Grove South neighborhood could have what you want, yet when you and your guilty pup walk in, owner Don Scherer promptly gets out the step ladder and pulls down five different kinds of door guards. He compares the mesh to the size of your dog's feet. He shows you six or seven types of window screen. The place is spotlessly clean and smells like grass seed. A burly tradesman stops to give the pooch a pat. You decide to keep the dog after all.