Toph loves to crawl up the stairs and he's getting pretty good at it. We like to let him get as far as he can on his own and when he falls, we say, "Did you learn a lesson?"
Nah, we don't do that really. We're actually crawling up the stairs right behind him, breathing down his neck, partially cheering for him because hey, he's crawling up the stairs, but also praying that he doesn't get overconfident and go too fast. Parenting; it's a fine line between letting them learn and not letting them fall. Hopefully we're providing an environment where he can freely learn while being safe.
Anyway, last night Toph was making a trek upstairs and his daddy was right behind him. For the first time, Toph noticed our "jail" on the landing between our first and second story.
They both had a good time with that.