DEF B1 Background {\n\
      skyColor [0 0 0, 1.0 1.0 1.0 ]\n\
      skyAngle 1.6\n\
      groundColor [1 1 1, 0.8 0.8 0.8, 0.2 0.2 0.2 ]\n\
      groundAngle [ 1.2 1.57 ]\n\
    }\n\
    DEF Wall Shape {\n\
      geometry Box {size 1 1 1}\n\
      appearance Appearance { material Material { diffuseColor 0 0 1 } }\n\
    }\n\
    DEF Entry Viewpoint {\n\
      position 0.5 1.0 5.0\n\
      orientation 0.0 0.0 -1.0 0.52\n\
    }\n"
    for (i in Maze) {
      split(i, t, SUBSEP)
      Document = Document "    Transform { translation "
      Document = Document t[1] " 0 -" t[2] " children USE Wall }\n"
    }
    Document = Document "  ] # end of group for world\n}"
    Reason = "OK" ORS "Content-type: model/vrml"
    Header = Footer = ""
  }
}
function MakeMaze(x, y) {
  delete Maze[x, y]     # here we are, we have no wall here
  p = 0                 # count unvisited fields in all directions
  if (x-2 SUBSEP y   in Maze) d[p++] = "-x"
  if (x   SUBSEP y-2 in Maze) d[p++] = "-y"
  if (x+2 SUBSEP y   in Maze) d[p++] = "+x"
  if (x   SUBSEP y+2 in Maze) d[p++] = "+y"
  if (p>0) {            # if there are unvisited fields, go there
    p = int(p*rand())   # choose one unvisited field at random
    if        (d[p] == "-x") { delete Maze[x - 1, y]; MakeMaze(x - 2, y)
    } else if (d[p] == "-y") { delete Maze[x, y - 1]; MakeMaze(x, y - 2)
    } else if (d[p] == "+x") { delete Maze[x + 1, y]; MakeMaze(x + 2, y)
    } else if (d[p] == "+y") { delete Maze[x, y + 1]; MakeMaze(x, y + 2)
    }                   # we are back from recursion
    MakeMaze(x, y);     # try again while there are unvisited fields
  }
}