Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical expressions, to represent images in computer graphics. ‘Vector’, in this context, implies more than a straight line. Vector graphics is based on images made up of vectors (also called paths, or strokes) which lead through locations called control points. Each of these points has a definite position on the x and y axes of the work plan. Color or colour is the visual perceptual property corresponding in humans to the categories called red, green, blue, and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc. , based on their physical properties such as light absorption, reflection, or emission spectra. In physics, coherence is an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference. It contains in fact several distinct concepts, which are limit cases that never occur in reality but allows to understand the physics of waves and has become in particular a very important concept in quantum physics. Source.