C     .TITLE CO-OP1
C
C  13 DEC 74 (PDH) DISPLAY BOX, PUT 'ITAG' IN COMMON
C  12 DEC 74 (PDH) CHANGE FOR INTERLACED FIGURES
C  30 OCT 74 (PDH) CALLS NOW AS FAR AS 'PART10'
C  28 OCT 74 (PDH) MORE WORK ON 'PART6'; SEPARATE PARTS FOR CHAINING
C  25 OCT 74 (PDH) DEBUG 'PART4'; ADD 'PART6'
C  24 OCT 74 (PDH) DEBUG 'PART3' & 'PART5'; ADD 'PART4'
C  23 OCT 74 (PDH) 'PART2' WORKS; ADD 'PART3', 'PART5'
C  18 OCT 74 - PAUL HENDERSON
C
      LOGICAL T/.TRUE./,ISENSW
      INTEGER BOX(10)/0,12415,73899,32772,65663,87296,65791,-11008,0,0/
      COMMON /LIMITS/XMIN,XMAX,YMIN,YMAX
      COMMON /ANGLES/PIBY4,PI5BY4,PI
      COMMON /TAGS/ITAG
C
   10 CALL CLEAR (T)
      CALL DISPLY (0,20000,IGET)
      IF (ISENSW(0)) WRITE (4,*) 'ASK 20000; GET',IGET
      PI     = 3.141593
      PIBY4  = PI/4.
      PI5BY4 = PIBY4*5.
C
  20  ITAG = 1
      CALL DISPLY (6,ITAG,BOX,1,10)
      WRITE (4,*) 'XMIN, XMAX, YMIN, YMAX (1)'
      READ  (4,*) XMIN,XMAX,YMIN,YMAX
      CALL CO
      CALL OP
      CALL DISPLY (7,IGET)
      IF (ISENSW (0)) WRITE (4,*) '''DISPLY'' CORE LEFT',IGET
C
      WRITE (4,*) 'XMIN, XMAX, YMIN, YMAX (2)'
      READ  (4,*) XMIN,XMAX,YMIN,YMAX
      CALL CO
      CALL OP
      CALL DISPLY (7,IGET)
      IF (ISENSW(0)) WRITE (4,*) '''DISPLY'' CORE LEFT',IGET
      PAUSE 1
      CALL DISPLY (8)
      GO TO 20
      END