The color gradients represent relief; Marune is a most rugged world.
For example, if given different-shaded objects they may make a color gradient.
The possibilities include patterns and color gradients for fills; corner, endpoint, pen-type and thickness for lines.
Then I would expect to see a much smaller color gradient on the start bar, from a light yellow to a dark yellow perhaps.
Rainbow Printing: A printing method whereby color gradients give a rainbow-like effect.
The logo shows six circles in decreasing size with a color gradient going from dark blue to red to white, featured on a yellow background.
Many libraries and cards provide color gradients, which are handy for the generation of smoothly-varying backgrounds, shadow effects, etc. (See also Gouraud shading).
An axial color gradient (sometimes also called a linear color gradient) is specified by two points, and a color at each point.
Users have full control of plot and label attributes, including background color, color gradients, size, and thickness.
Some cultivars have a color gradient, from white at the stem to bright pink to deep purple or even black.