I think that I like this but I would like a bit more explanation about the chalk. The character would be good for urban arcana or maybe a failed monk who got the physical training right but not the spiritual in a D&D game. Also what is the purpose of an acrobat? To be the best? Then why are they adventuring? And the chalk confuses me. What happens if you have some of a previous chalk on your hands when you use the next one? Do they combine in action or negate each other? If it becomes a weapon instead of an implement, does that mean that the acrobat no longer needs ki? Or more ki? As a weapon does that mean anyone can use it if the acrobat shares it around?
I could like this character a lot but I think it needs a little more tweaking.