Mimicking the pipe-wrench-jaw-like multistory balcony near the top of BG Group Place (seen in blocky form at right in the rendering above), there’ll a tree-toothed notch carved into the eastern edge of the top floors of the just-unveiled design for 6 Houston Center. But this new $250 million spec office tower won’t just be a little more roughly cut than its neighbor — it’ll be a bit shorter, too. The 30-story structure is planned for the block surrounded by Rusk, Walker, Caroline, and San Jacinto streets, directly north of the LyondellBasell Tower at 1 Houston Center, on what’s currently a surface parking lot.