abstract background blue colours cross graphic green light light rays orange black ferro iron lines metal shape square textura texture colour copper gold liquid reflect reflections ripple water color colors design rays shapes stripes air air balloon balloon blue sky bright bright colors hot air balloon palette primary colors red sky summer white cloud crescent evening moon pink twilight graph radar round spherical tomography violet yellow autumn blue-red glittering leaves october psychedelic purple tree trees hue rough water shadows water surface desktop Fractal fractals math mathematic mathematical mathematics maths