LAYER M1
  TYPE ROUTING ;
END M1
LAYER VIA1
  TYPE CUT ;
END VIA1

MACRO dense
  CLASS CORE ;
  ORIGIN 0.0 0.0 ;
  FOREIGN dense ;
  SIZE 0.7 BY 0.9 ;
  OBS
    LAYER M1 DESIGNRULEWIDTH 0.05 ;
      RECT 0.04 0.095 0.66 0.685 ;
    LAYER VIA1 ;
      RECT 0.285 0.31 0.415 0.36 ;
      RECT 0.285 0.18 0.415 0.23 ;
  END
  DENSITY
    LAYER M1 ;
      RECT 0.04 0.09 0.66 0.685 100.0 ;
    LAYER VIA1 ;
      RECT 0 0 100 100 45.5 ; #rect from (0,0) to (100,100), density of 45.5%
      RECT 100 0 200 100 42.2 ; #rect from (100,0) to (200, 100), density of 42.2%
  END
END dense
END LIBRARY