As you may have already noticed among the planet examples a planet appeared in which the form of continents resemble letters. This is the result of application of the algorithm which I called *the Ancient Alien Civilization method*, as it is similar to the result of terraforming the planet by a developed ancient civilization. Of course, the form of the continents can be any with taking into account the minimum step of the planet basic heights grid.

The method is based on the good old noise functions, but supplemented by what can be called *the imposition of a stencil*. When we calculate the value of a noise function at a point, we also check the value of a specific function at this point (*the stencil*), which can have a value of either 0 or 1. If it has value 1 we store the value of the noise function, and if it is 0 we assign to the result a value of 0.

Thus, *the stencil function* defines the shape of the continents. In the example of Mandelbrot planet it is zero everywhere except the location of the letters. Such kind of map details have a relatively large scale, in the size of the continents. To get smaller details of the map (for example, craters) we must apply them already on local grid of rombs. But this is still in development.

The last picture is the unfolded view of the Mandelbrot planet continents.