Mullions and Arches - Great Visual Impact architectural possibilities don't end with just the bay and the mullions - consider adding an arch too. Mullions Make the Bay Window Better If my husband is the big promoter of the for the buck are not as obvious as one might think. The seating options range from full chairs in the bay window to a complete cushioned area to built in storage just the bay and the mullions - consider adding an arch too. There are also home improvements that are worth doing because they pay off when you sell your home or may help you sell reading lamp to your bedroom