PLOT_COLOR draws a bidimensional dotted graph, where the color of every single point of the vectors X, Y depends by vector P (the intensity color, isn't necessary normalize it).
X, Y and P must be vector and must be have same lenght.
ColorStart and ColorEnd are the two colours that specifying the fractional position of blending. P determines the point to point percent of colour.
MarkerSize has the same sintax as when using it in the plot.
The screenshot was build with this code:
X = 0:100;
Y = sin(X).*exp(-.05.*X);
P = Y;
plot_color(X', Y', P', [1,0,0], [0,0,1], 6)
Update "Other requirements"