Note the hardwood 'pinstriping'. In the process of building the bike we had several bamboo pieces crack. This made us nervous, because we did not want to do all this work just to have a piece in the finished bike crack. So, we decided to 'crack' each large piece intentionally, by cutting a V-groove all the way through, thus releasing all the tension, and then filled the groove with a V-shaped piece of American black walnut. This added a pinstripe feature, which we were pleased with.