David, it’s interesting that you choose to face a blank white wall in the morning hours, when you’re engaged in your most creative work. The conventional wisdom is to do the opposite — that is, to orient ourselves towards a view of distant space, such as might be afforded through a window, in order to impress our minds with a sense of physical distance. The theory is that the more open we perceive the space around us to be, the more open we tend to be to new ideas.
Then again, there are some people who lack sufficient sensory filters to weed out the abundance of external stimuli that this exposure brings. To compensate, they take measures like the ones you describe. Apparently, you’re in good company; the writer Marcel Proust also had to use earplugs and cover his windows with drapes to block out street noise while working on his novels. Sounds like you two were cut from the same cloth!