To build a new tiles.png file, do the following:

1. Open a command-prompt, and cd to the graphics subdirectory.

2. Compile the helper program by typing the following command:

    javac MakeTiles.java

3. Build the new tiles.png file by typing this command:

    java MakeTiles tiles.dat tiles.png

   (This will create tiles.png in the current directory.
    Copying it into the ../resources/ directory and rebuilding
    Micropolis using Ant is left as an exercise for the reader.)