rastername=ninphet
autotrace -color-count 25 \
          -corner-always-threshold 10 \
          -corner-surround 24 \
          -corner-threshold 20 \
          -despeckle-level 10 \
          -despeckle-tightness 0.0 \
          -error-threshold 6.8 \
          -input-format PNG \
          -line-threshold 2 \
          -output-file $rastername.mp \
          -output-format mpost \
          -remove-adjacent-corners \
          $rastername.png
mpost $rastername.mp