actually, a wavy line, or an irregular line is a good idea. I've been thinking also about some fairly thin glass tiles in rectangular and square...
I like the look of a bathroom where the bottom 2/3 of the walls are white tile, and the top 1/3 of the walls is painted a color. I have no tile,...
Paint the trim and bottom half of wall the same neutral color, preferably white. Paint the top half of the wall the terra cotta as someone else...