def save_ascii(fn)
      o = open(fn, 'w')
      rows.times do |i|
        columns.times do |j|
          o.print get(i,j)
          o.print "\t" if j < columns - 1
        end
        o.puts
      end
      o.close
    end
def save_ascii(fn)
      o = open(fn, 'w')
      rows.times do |i|
        columns.times do |j|
          o.print get(i,j)
          o.print "\t" if j < columns - 1
        end
        o.puts
      end
      o.close
    end
Save as ascii (tab-separated list, every row is a line)