<div align="justify"> <p>Command: <br> image 400 200 'c=((x-(w-1)/2)^2+(y-h)^2)/((w*0.4)^2); c-0.5' f00,f80,ff0,0f0,0fa,00f,80f,f0f > rainbow.xpm</p> <p> The first expression "((x-(w-1)/2)^2+(y-h)^2)/((w*0.4)^2)" crates a circle with radial gradient. The outside the circle is made by pixels where the "c" value is greater than 1 (so transparent), and it's center is 0.</p> <p>The second expression makes the circle grows by reducing the pixel value, but also makes the center to be lower than 0, so transparent. </p> </div>