Decorator Abstractions: A decorator abstraction is an abstract class that implements the component interface. Critically, the decorator abstraction must also contain a pointer to some instance of the same interface. Inside the decorator abstraction, each of the component interface behaviors will be delegated to whichever concrete component the pointer indicates.
In 1890, the Parisian painter Maurice Denis famously asserted: "Remember that a painting—before being a warhorse, a naked woman or some story or other—is essentially a flat surface covered with colors assembled in a certain order." Thus, many 20th-century developments in painting, such as Cubism, were reflections on the means of painting rather than on the external world—nature—which had previously been its core subject. Recent contributions to thinking about painting have been offered by the painter and writer Julian Bell. In his book What is Painting?, Bell discusses the development, through history, of the notion that paintings can express feelings and ideas. In Mirror of The World, Bell writes:
None of these alternatives gained much traction. The alternatives which involve square brackets only serve to make it obvious that the decorator construct is not a list. They do nothing to make parsing any easier. The '<...>' alternative presents parsing problems because '<' and '>' already parse as un-paired. They present a further parsing ambiguity because a right angle bracket might be a greater than symbol instead of a closer for the decorators.
Color, made up of hue, saturation, and value, dispersed over a surface is the essence of painting, just as pitch and rhythm are the essence of music. Color is highly subjective, but has observable psychological effects, although these can differ from one culture to the next. Black is associated with mourning in the West, but in the East, white is. Some painters, theoreticians, writers and scientists, including Goethe, Kandinsky, and Newton, have written their own color theory.