Shouldn't even be typing code while planning. There's no software idea that needs to be coded as it's planned. It's just a waste of time, and potentially harmful. The devs I've worked with that "think" in classes, or tables, or whatever code structure they're most comfortable with, inevitably end up creating garbage in the first 10 minutes that ends up lasting the lifetime of the project, confusing the hell out of everyone that looks at it, including themselves a week later.