Bold and straightforward, nice textures as well. You could probably tweak the levels or curves to remove a bit of the greyness and really bring out the texture. A light sharpening might also help.
Your adjustments took away too much of the texture. The texture was a significant appeal to the original photograph. When messing with curves try and preserve the texture.
i want to see it in colour. it's bothering me that it's not an octogon and so i want to see if it's still red or something completely different. also, if it's not blue there could be some cool contrast with simple colours against a sky.