Hm. Well, first off, I think you should study perspective. Andrew Loomis did some helpful tutorials on that, and they can be found here: [link] It would definitely help with that pillar.
I think that doing studies from life would benefit you as well. Start small, with simple objects like a ball or a square to get the hand of how light works on different forms. Right now there's really no range in value, so there is no form being expressed and everything looks flat.
It's a sweet concept and I think that with time and work, it can be improved immensely!
I love the minimalism to this. It's a great concept. A more concrete sense of perspective would definitely help with pulling it off. You can do this by making sure the lines of the bricks all go back to the appropriate vanishing points. Also, a bit more contrast would help as well. Otherwise, nice job!