A shape element is currently either an Oval (including circles) or a Rectangle (including squares).
They are intended mainly for decoration and to act as backgrounds for other elements but can still perform click actions like all elements.
Shapes can be shaded. Shading involves gradually changing the paint colour from a user-specified start colour to a user-specified end colour as the shape is shaded.
Rectangles can have their corners rounded to match the general UI or to create a 'tab' appearance.