def bounding_box(visible_only = true)
      maxX = atoms(visible_only).first.x
      maxY = atoms(visible_only).first.y
      maxZ = atoms(visible_only).first.z
      minX = maxX
      minY = maxY
      minZ = maxZ
      
      atoms(visible_only).each{|a|
        if a.x > maxX
          maxX = a.x
        elsif a.x < minX
          minX = a.x
        end
        
        if a.y > maxY
          maxY = a.y
        elsif a.y < minY
          minY = a.y
        end
        
        if a.z > maxZ
          maxZ = a.z
        elsif a.z < minZ
          minZ = a.z
        end
      }

      [Atom.new(maxX, maxY, maxZ), Atom.new(minX, minY, minZ)]
    end
def bounding_box(visible_only = true)
      maxX = atoms(visible_only).first.x
      maxY = atoms(visible_only).first.y
      maxZ = atoms(visible_only).first.z
      minX = maxX
      minY = maxY
      minZ = maxZ
      
      atoms(visible_only).each{|a|
        if a.x > maxX
          maxX = a.x
        elsif a.x < minX
          minX = a.x
        end
        
        if a.y > maxY
          maxY = a.y
        elsif a.y < minY
          minY = a.y
        end
        
        if a.z > maxZ
          maxZ = a.z
        elsif a.z < minZ
          minZ = a.z
        end
      }

      [Atom.new(maxX, maxY, maxZ), Atom.new(minX, minY, minZ)]
    end
Return a two element array contaiing two artificial Aims::Atom objects whose coordinates
 represent the lower-left and upper-right corners of the Geometry's bounding box.