Orbits of Martin's Map

This is the two-dimensional map known as Martin's map: , y_k+1=a-x_k
Orbits are generated by iterating the map n times using different initial points. The map parameters a, b and c can be varied manually or a random set can be launched.
Three orbits are plotted initially, starting from three different initial points marked by Locator objects "⊕". You can move these initial points around or add and/or delete new ones by Alt+Click inside the plot. Three orbit colors are used cyclically.