SUBROUTINE  PLTKY (Z1,ZE,Z2,NX,NY,PL)

C     [Y CROSSHATCHING]
C     ZE(NX,NY)   DATA ARRAY
C     (Z1,Z2)     INTERVAL TO BE MARKED
C     PL          PEN MOVEMENT SUBROUTINE, PERHAPS PLTCA
C     [05-JAN-75]

      EXTERNAL    PL
      DIMENSION   ZE(1)

      IX(I,J)=I+NX*(J-1)
      VI(Z)=(Z-Z1)*(Z2-Z)

      X=1.0
      Y=1.0
      DX=-1.0/FLOAT(NX-1)
      DY=-1.0/FLOAT(NY-1)
      DO 30 I=1,NX,2
      CALL PL (X,Y,.FALSE.)
      DO 10 J=2,NY
      I1=IX(NX-I+1,NY-J+2)
      I2=IX(NX-I+1,NY-J+1)
      CALL PLTIL (X,Y,VI(ZE(I1)),X,Y+DY,VI(ZE(I2)),PL)
   10 Y=Y+DY
      DY=-DY
      X=X+DX
      IF (I.GE.NX) RETURN
      CALL PL (X,Y,.FALSE.)
      DO 20 J=2,NY
      I1=IX(NX-I,J-1)
      I2=IX(NX-I,J)
      CALL PLTIL (X,Y,VI(ZE(I1)),X,Y+DY,VI(ZE(I2)),PL)
   20 Y=Y+DY
      DY=-DY
   30 X=X+DX
      RETURN

      END