In the fading example at TikZ examples
I would like to change the "speed" at which fade occurs. In fact I would like it to be very "sharp" so that in the square examples you basically will see about half a square because it fades out so quick.
Any ideas how to achieve that? (basically I want to overlay two squares with different colors and end up seeing half a square of one color and the other half the other color but with a sort of quick fade between the two in the center(instead of the gradual fade that the default tikz setup gives)