This is a useful tool. It shows if a surface level. Has 1 and 2 Dimension modes.
Set your phone or other device on a surface and this application will tell you if the surface is level or not. It simulates the bubble in a carpenters level that floats back and forth. When the bubble is inside the lines your surface is close to level. When the boundary lines change color, your surface is as level as it can be measure at the set precision level. There are three accuracy settings.