Manyland

A Far Back is a structure in the distance. You find it in the Back category of the creator. You can use several large cells, and the points of a polygon:

-300 70 
-250 30 
-220 40 
-200 30 
-180 50 
-150 -20 CELL 3 
-100 0 
0 0 1 
100 0 
 
// more 
120 40 
130 60 
150 50 CELL 2 
200 80 

Each line consists of the x and y coordinate forming the Far Back's upper polygon line, plus an optional CELL keyword with a number indicating the cell you want to show there (like a glossy mountaintop, trees, huts and anything you can imagine). The double slash "//" indicates a comment, and newlines can be used freely.

To display a cell at a slightly different position than the polygon's point, you can use an offset like this:

... 
50 50 CELL 1 -10 20 
... 

You can also fully disconnect it from the polygon like this:

... 
CELL 1 -50 30 
... 

The first color used in your Far Back's palette during creation is the color the polygon will use, too. You can use up to 100 coordinates, each with values from -500 to 500 (-300 to 300 for cell coordinates), and display images up to 30 times.