PARAMETER MAXH=52		!MAXIMUM NUMBER OF HORIZONTAL SQUARES
      PARAMETER MAXV=170	!MAXIMUM NUMBER OF VERTICAL SQUARES
C     MAZE PROGRAM
      INTEGER H
      INTEGER X,T,C,R,S,VV,Z,Q
      INTEGER W(MAXH, MAXV),V(MAXH, MAXV)
      COMMON I1,I2
      INIT=AMOD(SECNDS(0.),200.)
      DO 1 I=1,INIT
1     X=RAN(I1,I2)
9000  FORMAT (1X,131A1)
9001  WRITE(5,100) 
100   FORMAT('$ENTER MAZE SIZE (HORZ,VERT) > ')
      READ(5,110,END=99) H,VV
110   FORMAT(2I10)
      H=MIN0(H,MAXH)
      VV=MIN0(VV,MAXV)
      Q=0
      Z = 0
      DO 40 J=1,MAXH
      DO 40 I=1,MAXV
      W(J,I)=0
40    V(J,I)=0
      X=IRAND (H)
      KK=X
      C=1
      W(X,1)=C
      C=C+1
      R=X
      S=1
      GO TO 900
730   IF (R.NE.H) GO TO 810
      IF (S.NE.VV) GO TO 780
      R=1
      S=1
      GO TO 890
780   R=1
      S=S+1
      GO TO 890
810   R=R+1
890   IF (W(R,S).EQ.0) GO TO 730
900   IF (R .EQ. 1) GO TO 1330
      IF (W(R-1,S) .NE. 0) GO TO 1330
      IF (S .EQ. 1) GO TO 1100
      IF (W(R,S-1).NE.0) GO TO 1100
      IF (R.EQ.H) GO TO 990
      IF  (W(R+1,S).NE.0) GO TO 990
      X=IRAND(3)
      GO TO (1850,1920,1990),X
990   IF (S.NE.VV) GO TO 1030
      IF (Z.EQ.1) GO TO 1070
      Q=1
      GO TO 1040
1030  IF (W(R,S+1).NE.0) GO TO 1070
1040  X=IRAND(3)
      GO TO (1850,1920,2090),X
1070  X=IRAND(2)
      GO TO (1850,1920),X
1100  IF (R.EQ.H) GO TO 1230
      IF (W(R+1,S).NE.0) GO TO 1230
      IF (S.NE.VV) GO TO 1160
      IF (Z.EQ .1) GO TO 1200
      Q=1
      GO TO 1170
1160  IF (W(R,S+1).NE .0) GO TO 1200
1170  X=IRAND(3)
      GO TO (1850,1990,2090),X
1200  X=IRAND(2)
      GO TO (1850,1990),X
1230  IF (S.NE .VV) GO TO 1270
      IF (Z.EQ .1) GO TO 1850
      Q=1
      GO TO 1280
1270  IF (W(R,S+1).NE .0) GO TO 1850
1280  X=IRAND(2)
      GO TO (1850,2090),X
1330  IF (S .EQ. 1) GO TO 1580
      IF (W(R,S-1).NE .0) GO TO 1580
      IF (R.EQ .H) GO TO 1480
      IF (W(R+1,S).NE .0) GO TO 1480
      IF (S.NE .VV) GO TO 1410
      IF (Z .EQ. 1) GO TO 1450
      Q=1
      GO TO 1420
1410  IF (W(R,S+1).NE .0) GO TO 1450
1420  X=IRAND(3)
      GO TO (1920,1990,2090),X
1450  X=IRAND(2)
      GO TO (1920,1990),X
1480  IF (S.NE .VV) GO TO 1520
      IF (Z.EQ .1) GO TO 1920
      Q=1
      GO TO 1530
1520  IF (W(R,S+1).NE .0) GO TO 1920
1530  X=IRAND(2)
      GO TO (1920,2090),X
1580  IF (R.EQ .H) GO TO 1700
      IF (W(R+1,S).NE .0) GO TO 1700
      IF (S.NE .VV) GO TO 1640
      IF (Z.EQ. 1) GO TO 1990
      Q=1
      GO TO 1650
1640  IF (W(R,S+1).NE .0) GO TO 1990
1650  X=IRAND(2)
      GO TO (1990,2090),X
1700  IF (S.NE .VV) GO TO 1740
      IF (Z.EQ .1) GO TO 730
      Q=1
      GO TO 2090
1740  IF (W(R,S+1).NE .0) GO TO 730
      GO TO 2090
1850  W(R-1,S)=C
      C=C+1
      V(R-1,S)=2
      R=R-1
      IF (C.EQ .H*VV+1) GO TO 2310
      Q=0
      GO TO 900
1920  W(R,S-1)=C
      C=C+1
      V(R,S-1)=1
      S=S-1
      IF (C.EQ .(H*VV+1)) GO TO 2310
      Q=0
      GO TO 900
1990  W(R+1,S)=C
      C=C+1
      IF (V(R,S).EQ .0) GO TO 2040
      V(R,S)=3
      GO TO 2050
2040  V(R,S)=2
2050  R=R+1
      IF (C.EQ .(H*VV+1)) GO TO 2310
      Q=0
      GO TO 1330
2090  IF (Q.EQ. 1) GO TO 2190
      W(R,S+1)=C
      C=C+1
      IF (V(R,S).EQ .0) GO TO 2150
      V(R,S)=3
      GO TO 2160
2150  V(R,S)=1
2160  S=S+1
      IF (C.EQ .(H*VV+1)) GO TO 2310
      GO TO 900
2190  Z=1
      IF (V(R,S).EQ .0) GO TO 2240
      V(R,S)=3
      Q=0
      GO TO 730
2240  V(R,S)=1
      Q=0
      R=1
      S=1
      GO TO 890
2310  CALL PLOTS(.2*FLOAT(VV)+.5,.2*FLOAT(H)+.5)
      Y=.2*FLOAT(KK)
      CALL PLOT(0.,Y,3)
      CALL PLOT(.1,Y,2)
      CALL PLOT(0.,Y+.2,3)
      CALL PLOT(.1,Y+.2,2)
C
      CALL PLOT(.1,0.,3)
      CALL PLOT(.1,Y,2)
      CALL PLOT(.1,Y+.2,3)
      CALL PLOT(.1,.2*FLOAT(H),2)
C
      XX=.1
      DO 3000 J=1,VV
      CALL PLOT(XX,0.,3)
      CALL PLOT(XX+.2,0.,2)
      DO 3001 I=1,H
      IF (V(I,J).GT.1) GO TO 3001
      Y=FLOAT(I)*.2
      CALL PLOT(XX,Y,3)
      CALL PLOT(XX+.2,Y,2)
3001  CONTINUE
      XX=XX+.2
      DO 3002 I=1,H
      IF (V(I,J).EQ.1.OR.V(I,J).EQ.3) GO TO 3002
      Y=.2*FLOAT(I-1)
      CALL PLOT(XX,Y,3)
      CALL PLOT(XX,Y+.2,2)
3002  CONTINUE
3000  CONTINUE
      DO 3003 I=1,H
      IF (V(I,VV).EQ.0.OR.V(I,VV).EQ.2) GO TO 3003
      Y=.2*FLOAT(I-1)
      CALL PLOT(XX,Y,3)
      CALL PLOT(XX+.1,Y,2)
      CALL PLOT(XX,Y+.2,3)
      CALL PLOT(XX+.1,Y+.2,2)
      GO TO 3004
3003  CONTINUE
3004  CALL PLOT(0.,0.,999)
3999  CONTINUE
C      GO TO 9001
99    STOP
      END
      FUNCTION IRAND(I)
      COMMON I1,I2
      X=RAN(I1,I2)
      IRAND=X*FLOAT(I)+1.
      RETURN
      END