//JOB(ERCC07,STEPHENS,T=200,L=10000)
//OPTIONS(QUOTES,OPT)
//ALGOL
'COMMENT'
                         ***************
                         *             *
                         *   ALGG050   *
                         *             *
                         ***************
;
 'BEGIN'

'BEGIN' 'COMMENT' TEST PROGRAM MK.2;
'COMMENT'   JFMP2  ;
      'COMMENT' A0,A6;
      'REAL' XLIM,YLIM,TLIM,GAPX,GAPY,H;

      XLIM:=READ;  YLIM:=READ;  TLIM:=READ;
      GAPX:=READ;  GAPY:=READ;     H:=READ;
'BEGIN'
      'REAL' X,Y,T,K,W,G,B,C,INTA,INC,DTL;
      'INTEGER' N,COUNT;
      'ARRAY'  U[0:XLIM,1:YLIM+1,0:1],V[0:XLIM,1:YLIM+1,0:1],
              A[0:XLIM,1:YLIM+1,0:1],
              M[0:5],S[0:5],UP[0:5],VP[0:5],AP[0:5],
              DISX[0:5],DISY[0:5],UX[0:4],UY[0:4],VX[0:4],VY[
0:4],
              AX[0:4],AY[0:4],E2[0:5],E3[0:5],E4[0:5],
                 CASE[0:XLIM,1:YLIM+1],AC[0:TLIM];
      'PROCEDURE' INTER1(VAR,VARP,VARPX,VARPY);
      'ARRAY' VAR,VARP,VARPX,VARPY;
'BEGIN'
      'REAL' XYP,YYP,XXP,YXP,XAP,YAP,DVRDX1,DVRDX2,DVRDY1,DVRDY2;
      XYP:=X;  YXP:=Y;
      'IF' DISX[N]<0 'AND' DISY[N]<0 'THEN'
'BEGIN'
      YYP:=Y-1;
      XXP:=X-1;
      XAP:=X-1;
      YAP:=Y-1;
'END';
      'IF' DISX[N]<0 'AND' DISY[N]>0 'THEN'
'BEGIN'
      YYP:=Y+1;
      XXP:=X-1;
      XAP:=X-1;
      YAP:=Y+1;
'END';
      'IF' DISX[N]>0 'AND' DISY[N]>0 'THEN'
'BEGIN'
      YYP:=Y+1;
      XXP:=X+1;
      XAP:=X+1;
      YAP:=Y+1;
'END';
      'IF' DISX[N]>0 'AND' DISY[N]<0 'THEN'
'BEGIN'
      YYP:=Y-1;
      XXP:=X+1;
      XAP:=X+1;
      YAP:=Y-1;
'END';
       DVRDX1:=(VAR[XXP,YXP,0]-VAR[X,Y,0])*(SIGN(XXP-X))/GAPX;
       DVRDY1:=(VAR[XYP,YYP,0]-VAR[X,Y,0])*(SIGN(YYP-Y))/GAPY;
       DVRDX2:=(VAR[XAP,YAP,0]-VAR[XYP,YYP,0])*(SIGN(XXP-X))/GAPX;
       DVRDY2:=(VAR[XAP,YAP,0]-VAR[XXP,YXP,0])*(SIGN(YYP-Y))/GAPY;
      VARP[N]:=VAR[X,Y,0]+DVRDX1 *(DISX[N])+DVRDY1*(DISY[N]);
      VARPX[N]:=DVRDX1 +(ABS(DISY[N])/GAPY)*(DVRDX2 - DVRDX1);
      VARPY[N]:=DVRDY1 +(ABS(DISX[N])/GAPX)*(DVRDY2 - DVRDY1);
'END' INTER1;
'PROCEDURE' INTER2(VAR,VARP,VARPX,VARPY);
      'ARRAY' VAR,VARP,VARPX,VARPY;
'BEGIN'
      'IF' CASE[X,Y]=1 'THEN'
      'BEGIN' VARPX[0]:=0; VARPX[2]:=0; VARPX[4]:=0;
      'IF' DISX[0]<0 'THEN' VARPY[0]:=(VAR[X,Y,0]-VAR[X,Y-1,0])/
GAPY
               'ELSE' VARPY[0]:=(VAR[X,Y+1,0]-VAR[X,Y,0])/GAPY;
      VARPY[2]:=(VAR[X,Y,0]-VAR[X,Y-1,0])/GAPY;
      VARPY[4]:=(VAR[X,Y+1,0]-VAR[X,Y,0])/GAPY;
      VARP[0]:=VAR[X,Y,0]+VARPY[0]*DISY[0];
      VARP[2]:=VAR[X,Y,0]+VARPY[2]*DISY[2];
      VARP[4]:=VAR[X,Y,0]+VARPY[4]*DISY[4];
'END';
'END' INTER2;
      'PROCEDURE' INTER3(VAR,VARP);
      'ARRAY' VAR,VARP;
      'BEGIN' 'REAL' A1,A2;
      'FOR' N:=0 'STEP' 1 'UNTIL' 4 'DO'
      'BEGIN'
      A1:=DISX[N]*(VAR[X+1,Y,0]-VAR[X-1,Y,0])/(2*GAPX);
     A1:=A1+(DISX[N]**2)*(VAR[X+1,Y,0]+VAR[X-1,Y,0]-2*VAR[X,Y,0]
     )/(2*(GAPX**2));
      A2:=DISY[N]*(VAR[X,Y+1,0]-VAR[X,Y-1,0])/(2*GAPY);
     A2:=A2+(DISY[N]**2)*(VAR[X,Y+1,0]+VAR[X,Y-1,0]-2*VAR[X,Y,0]
     )/(2*(GAPY)**2);
      VARP[N]:=VAR[X,Y,0]+A1+A2;
      'END';
'END' INTER3;
      'PROCEDURE' INTER4(VAR,VARP,VARPX,VARPY,X,Y);
      'VALUE' X,Y;  'ARRAY' VAR,VARP,VARPX,VARPY;  'REAL' X,Y;
      'BEGIN'  'REAL' A1,A2;
      'IF' CASE[X,Y]=7 'OR' CASE[X,Y]=27 'THEN'
      'BEGIN'
      X:=X-1;
      VARPX[N]:=(VAR[X+1,Y,0]-VAR[X,Y,0])/GAPX;
      VARPY[N]:=(VAR[X,Y+1,0]-VAR[X,Y-1,0]+VAR[X+1,Y+1,0]-VAR[X
+1,Y-1,0]
)/(4*GAPY);
      'END';
      'IF' CASE[X,Y]=8 'OR' CASE[X,Y]=81 'THEN'
      'BEGIN'
      Y:=Y+1;
      VARPX[N]:=(VAR[X+1,Y-1,0]-VAR[X-1,Y-1,0]+VAR[X+1,Y,0]-VAR[
X-1,Y,0]
)/(4*GAPX);
      VARPY[N]:=(VAR[X,Y,0]-VAR[X,Y-1,0])/GAPY;
      'END';
      'IF' CASE[X,Y]=78 'THEN'
      'BEGIN'
      X:=X-1;Y:=Y+1;
      VARPX[N]:=(VAR[X+1,Y,0]-VAR[X,Y,0]+VAR[X+1,Y-1,0]-VAR[X,Y
-1,0])/(2
*GAPX);
      VARPY[N]:=(VAR[X+1,Y,0]-VAR[X+1,Y-1,0]+VAR[X,Y,0]-VAR[X,Y
-1,0])/(2
*GAPY);
      'END';
      A1:=DISX[N]*(VAR[X+1,Y,0]-VAR[X-1,Y,0])/(2*GAPX);
     A1:=A1+(DISX[N]**2)*(VAR[X+1,Y,0]+VAR[X-1,Y,0]-2*VAR[X,Y,0]
      )/(2*(GAPX**2));
      A2:=DISY[N]*(VAR[X,Y+1,0]-VAR[X,Y-1,0])/(2*GAPY);
     A2:=A2+(DISY[N]**2)*(VAR[X,Y+1,0]+VAR[X,Y-1,0]-2*VAR[X,Y,0]
      )/(2*(GAPY**2));
      VARP[N]:=VAR[X,Y,0]+A1+A2;
'END' INTER4;
      'PROCEDURE' TRAVEL1;
'BEGIN'
      'IF' COUNT=1 'THEN'
      'BEGIN'  DISX[N]:=0; DISY[N]:=0;
      UP[N]:=U[X,Y,0];
      VP[N]:=V[X,Y,0];
      AP[N]:=A[X,Y,0];
      'END';
      'IF' N=0 'THEN'
      'BEGIN'  DISX[N]:=-(H/2)*(UP[5]+UP[N]);
              DISY[N]:=-(H/2)*(VP[5]+VP[N]);
      'END';
      'IF' N>0 'THEN' 'BEGIN'
      DISX[N]:=-(H/2)*(UP[5]+UP[N]+AP[5]*COS(M[N])+AP[N]*COS
(M[N]));
      DISY[N]:=-(H/2)*(VP[5]+VP[N]+AP[5]*SIN(M[N])+AP[N]*SIN
(M[N]));
      'END';
'END' TRAVEL1;
      'PROCEDURE' SOLVE1;
'BEGIN'
      'REAL' B1,B2,B3,C1,C2,C3,CON1,CON2,INTU,INTV,COUNTER;
      'FOR' N:=1 'STEP' 1 'UNTIL' 4 'DO'
      'BEGIN'  E4[N]:=-G*(B+C*SQRT((UP[N])**2+(VP[N])**2));
              E2[N]:=E4[N]*UP[N];
              E3[N]:=E4[N]*VP[N];
      'END';
      B1:=2*(AP[3]-AP[1])-UP[1]/K-UP[3]/K;
      B2:=2*(AP[4]-AP[2])-VP[2]/K-VP[4]/K;
      C1:=-E2[1]*H/2-E2[3]*H/2;
      C2:=-E3[2]*H/2-E3[4]*H/2;
      COUNTER:=0;
LOOP: E4[5]:=-G*(B+C*SQRT((UP[5])**2+(VP[5])**2));
      COUNTER:=COUNTER+1;
       E2[5]:=E4[5]*UP[5];
       E3[5]:=E4[5]*VP[5];
      CON1:=E2[5]*H-C1-B1;
      CON2:=E3[5]*H-C2-B2;
      INTV:=K*CON2/2;
      INTU:=K*CON1/2;
      'IF' COUNTER=4 'THEN' 'GOTO' NEXT;
      UP[5]:=UP[5]+0.54*(INTU-UP[5]);
      VP[5]:=VP[5]+0.54*(INTV-VP[5]);
      'GOTO' LOOP;
NEXT: UP[5]:=(UP[5]+INTU)/2;
       VP[5]:=(VP[5]+INTV)/2;
      B3:=-2*(AP[1]+AP[2]+AP[3]+AP[4]-2*AP[0])-UP[1]/K
          +UP[3]/K-VP[2]/K+VP[4]/K;
      C3:=(E2[1]+E3[2]-E2[3]-E3[4])*H/2;
      AP[5]:=-(B3+C3)/4;
'END' SOLVE1;
      'PROCEDURE' SOLVE 2;
      'BEGIN' 'REAL' A1,A2,A3,A4,A5,INT;
      'FOR' N:=1 'STEP' 1 'UNTIL' 4 'DO'
      'BEGIN'  E4[N]:=-G*(B+C*SQRT((UP[N])**2+(VP[N])**2));
               E2[N]:=E4[N]*UP[N];
               E3[N]:=E4[N]*VP[N];
               S[N]:=SIN(M[N])*(COS(M[N])*UY[N]-SIN(M[N])*UX[
N])/K
                     -COS(M[N])*(COS(M[N])*VY[N]-SIN(M[N])*VX[N
])/K;
      'END';
      'IF' CASE[X,Y]=1 'THEN'
      'BEGIN'
LL2:  E3[5]:=-G*(B*(VP[5])+C*((VP[5])**2));
      A1:=2*(AP[4]-AP[2])-VP[2]/K-VP[4]/K-E3[5]*H
         -(AP[2]*S[2]-AP[4]*S[4])*H/2
      -(E3[2]+E3[4])*H/2;
      INT:=-K*A1/2;
      'IF' ABS((INT-VP[5])/VP[5])<0.005 'THEN' 'GOTO' LL3;
      VP[5]:=(INT+VP[5])/2;
      'GOTO' LL2;
LL3:  VP[5]:=(INT+VP[5])/2;
      'END';
      'IF' CASE[X,Y]=2 'THEN'
      'BEGIN'
LL5:  E2[5]:=-G*(B*UP[5]+C*(UP[5]) **2);
      A1:=2*(AP[3]-AP[1])-UP[1]/K-UP[3]/K-E2[5]*H
         -(AP[1]*S[1]-AP[3]*S[3])*H/2
      -(E2[1]+E2[3])*H/2;
      INT:=-K*A1/2;
      'IF' ABS((INT-UP[5])/UP[5])<0.005 'THEN' 'GOTO' LL4;
      UP[5]:=(UP[5]+INT)/2;
      'GOTO' LL5;
LL4:  UP[5]:=(UP[5]+INT)/2;
      'END';
      A2:=2*(AP[1]+AP[2]+AP[3]+AP[4]-AP[0]);
      A3:=UP[1]/K-UP[3]/K+VP[2]/K-VP[4]/K;
      A4:=(E2[1]+E3[2]-E2[3]-E3[4])*H/2;
      A5:=(AP[1]*S[1]+AP[2]*S[2]+AP[3]*S[3]+AP[4]*S[4])*
H/2;
      AP[5]:=(A2+A3+A4+A5)/6;
'END' SOLVE 2;
      'PROCEDURE' SOLVE 3;
'BEGIN'
      'REAL' A1,A2,A3,A4,INTU,INTV;
      'ARRAY' UU[1:4],VV[1:4];
      'INTEGER' P,Q,I,J;
      UU[1]:=1/K; UU[2]:=0; UU[3]:=-1/K; UU[4]:=0;
      VV[1]:=0; VV[2]:=1/K; VV[3]:=0; VV[4]:=-1/K;
      'IF' CASE[X,Y]=5 'THEN'
      'BEGIN'
      I:=2; J:=4; P:=4; Q:=3;
      'END';
      'IF' CASE[X,Y]=6 'THEN'
      'BEGIN'
      I:=1; J:=3; P:=1; Q:=2;
      'END';
      'IF' CASE[X,Y]=7 'OR' CASE[X,Y]=27 'THEN'
      'BEGIN'
      I:=2; J:=4; P:=2; Q:=1;
      'END';
      'IF' CASE[X,Y]=8 'OR' CASE[X,Y]=81 'THEN'
      'BEGIN'
      I:=1; J:=3; P:=3; Q:=4;
      'END';
      'FOR' N:=I,J,Q 'DO'
      'BEGIN'
            E4[N]:=-G*(B+C*SQRT((UP[N])**2+(VP[N])**2));
            E2[N]:=E4[N]*UP[N];
            E3[N]:=E4[N]*VP[N];
      'END';
      A1:=-2*(AP[J]-AP[I])
         +UU[I]*UP[I]-UU[J]*UP[J]+VV[I]*VP[I]-VV[J]*VP[J]
;
      A2:=(E2[I]*COS(M[I])+E3[I]*SIN(M[I])
          -E2[J]*COS(M[J])-E3[J]*SIN(M[J]))*H/2;
      A3:=-2*AP[5]-2*AP[0]+2*AP[Q]+2*AP[P]
          +UU[P]*UP[P]+UU[Q]*UP[Q]+VV[P]*VP[P]+VV[Q]*VP[Q
];
      A4:=(E2[P]*COS(M[P])+E3[P]*SIN(M[P])
          +E2[Q]*COS(M[Q])+E3[Q]*SIN(M[Q]))*H/2;
LS31:  E4[5]:=-G*(B+C*SQRT((UP[5]**2)+ (VP[5]**2)));
       E2[5]:=E4[5]*UP[5];
       E3[5]:=E4[5]*VP[5];
      'IF' CASE[X,Y]=5 'THEN'
      'BEGIN'
      INTU:=(A3+A4+E2[5]*H/2+E3[5]*H/2)*K+(A1+A2+E3[5]*H)*K/2;
      INTV:=(A1+A2+E3[5]*H)*K/2;
      'END';
      'IF' CASE[X,Y]=6 'THEN'
      'BEGIN'
      INTV:=(A3+A4+E2[5]*H/2+E3[5]*H/2)*K-(A1+A2+E2[5]*H)*K/2;
      INTU:=(A1+A2+E2[5]*H)*K/2;
      'END';
'IF' CASE[X,Y]=7 'OR' CASE[X,Y]=27  'THEN'
      'BEGIN'
      INTU:=(A3+A4+E2[5]*H/2+E3[5]*H/2)*K-(A1+A2+E3[5]*H)*K/2;
      INTV:=(A1+A2+E3[5]*H)*K/2;
      'IF' ABS((INTU-UP[5])/UP[5])<0.001 'THEN' 'GOTO' LS32;
      'END';
      'IF' CASE[X,Y]=8 'OR' CASE[X,Y]=81   'THEN'
      'BEGIN'
      INTV:=-(A3+A4-E2[5]*H/2-E3[5]*H/2)*K-(A1+A2+E2[5]*H)*K/2;
      INTU:=(A1+A2+E2[5]*H)*K/2;
      'IF' ABS((INTV-VP[5])/VP[5])<0.001 'THEN' 'GOTO' LS32;
      'END';
      UP[5]:=(UP[5]+INTU)/2;
      VP[5]:=(VP[5]+INTV)/2;
      'GOTO' LS31;
LS32: UP[5]:=(UP[5]+INTU)/2;
      VP[5]:=(VP[5]+INTV)/2;
'END' SOLVE 3;
      'PROCEDURE' SOLVE78;
      'BEGIN' 'REAL' A1,A2,A3,INTU;
      A1:=(2*AP[1]+2*AP[4]-3*AP[5]-AP[0])*K/2;
      A2:=(AP[1]*VY[1]+AP[4]*UX[4])*H/4;
LS781:  'FOR' N:=1,4,5 'DO'
      'BEGIN' E4[N]:=-G*(B+C*SQRT((UP[N]**2)+(VP[N]**2)));
             E2[N]:=E4[N]*UP[N];
             E3[N]:=E4[N]*VP[N];
      'END';
      A3:=(E2[5]-E3[5]+E2[1]-E3[4])*H*K/4;
      INTU:=UP[5];
      UP[5]:=(UP[5]+(UP[1]-VP[4])/2+A1+A3)/2;
      'IF' ABS((INTU-UP[5])/UP[5])>0.001 'THEN' 'GOTO' LS781;
      VP[5]:=-UP[5];
      'END' SOLVE78;
      'FOR' X:=1 'STEP' 1 'UNTIL' XLIM 'DO'
      'BEGIN'
      'FOR' Y:=1 'STEP' 1 'UNTIL' YLIM 'DO'
      'BEGIN'
     U[X,Y,0]:=READ;V[X,Y,0]:=READ;A[X,Y,0]:=READ;
      CASE[X,Y]:=READ;
      'END'; 'END';
      B:=READ; C:=READ;
      G:=READ; K:=READ; W:=READ; INC:=READ;
      DTL:=ENTIER(INC/H);
      'FOR' T:=0 'STEP' DTL 'UNTIL' TLIM 'DO' AC[T]:=READ;
      N:=0;
LOOPD:'FOR' T:=(N*DTL+1) 'STEP' 1 'UNTIL'((N+1)*DTL-1) 'DO'
      AC[T]:=AC[N*DTL]+((AC[(N+1)*DTL]-AC[N*DTL])*(T-N*DTL)/DTL)
;
      N:=N+1;
      'IF' (N+1)*DTL<(TLIM+1) 'THEN' 'GOTO' LOOPD;
      T:=READ;


NEWLINES(1);
      WRITE TEXT ('('%%X%%%Y')');
NEWLINES(1);
BACK1:  WRITE TEXT('('TIME%%LEVEL%%IS%%')');
      PRINT(T,3,0);
      NEWLINES(1);
      'FOR' Y:=1 'STEP' 1 'UNTIL' YLIM 'DO'
      'BEGIN'
      U[0,Y,0]:=-U[2,Y,0]; V[0,Y,0]:=V[2,Y,0]; A[0,Y,0]:=A[2,
Y,0];
      'END';
      'FOR' X:= 1 'STEP' 1 'UNTIL' XLIM 'DO'
'BEGIN'
      U[X,YLIM+1,0]:=U[X,YLIM-1,0];
      V[X,YLIM+1,0]:=-V[X,YLIM-1,0];
      A[X,YLIM+1,0]:=A[X,YLIM-1,0];
      'END';
      U[0,YLIM+1,0]:=-U[2,YLIM-1,0];
      V[0,YLIM+1,0]:=-V[2,YLIM-1,0];
      A[0,YLIM+1,0]:=A[2,YLIM-1,0];
      X:=1; Y:=1;
BACK2:M[1]:=0; M[2]:=3.141593/2; M[3]:=3.141593; M[4]:=1.5*3.141
593;
      COUNT:=1;
      UP[5]:=U[X,Y,0]; VP[5]:=V[X,Y,0]; AP[5]:=A[X,Y,0];
      'IF' CASE[X,Y]=0 'THEN'
      'BEGIN'
LOOP: INTA:=AP[5];
      'FOR' N:=0 'STEP' 1 'UNTIL' 4 'DO'
            TRAVEL1;
            INTER3(U,UP);
            INTER3(V,VP);
            INTER3(A,AP);
      SOLVE1;
 COUNT:=COUNT+1;
      'IF' ABS((INTA-AP[5])/INTA)>0.001 'THEN' 'GOTO' LOOP;
      'END';
      'IF' CASE[X,Y]=1 'THEN'
      'BEGIN'
CYCLE: INTA:=AP[5];
      'FOR' N:=0 'STEP' 1 'UNTIL' 4 'DO' TRAVEL1;
            INTER3(U,UP);
            INTER3(V,VP);
            INTER3(A,AP);
      SOLVE1;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-AP[5])/INTA)>0.001 'THEN' 'GOTO' CYCLE;
      'END';
      'IF' CASE[X,Y]=2 'THEN'
      'BEGIN'
LOOP2: INTA:=AP[5];
      'FOR' N:=0 'STEP' 1 'UNTIL' 4 'DO' TRAVEL1;
            INTER3(U,UP);
            INTER3(V,VP);
            INTER3(A,AP);
      SOLVE1;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-AP[5])/AP[5])>0.001 'THEN' 'GOTO' LOOP2;
      'END';
      'IF' CASE[X,Y]=7 'THEN'
      'BEGIN'  AP[5]:=AC[T+1];
LOOP3: INTA:=UP[5];
      'FOR' N:=0,1,2,4 'DO'
      'BEGIN'
            TRAVEL1;
            DISX[N]:=GAPX+DISX[N];
            INTER4(U,UP,UX,UY,X,Y);
            INTER4(V,VP,VX,VY,X,Y);
            INTER4(A,AP,AX,AY,X,Y);
      'END';
      SOLVE3;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-UP[5])/UP[5])>0.005 'THEN' 'GOTO' LOOP3;
'END';
      'IF' CASE[X,Y]=12 'THEN'
      'BEGIN'
LOOP7:  INTA:=AP[5];
      'FOR' N:=0 'STEP' 1 'UNTIL' 4 'DO' TRAVEL1;
            INTER3(U,UP);
            INTER3(V,VP);
            INTER3(A,AP);
      SOLVE1;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-AP[5])/AP[5])>0.001 'THEN' 'GOTO' LOOP7;
      'END';
      'IF' CASE[X,Y]=27 'THEN'
      'BEGIN' AP[5]:=AC[T+1];
LOOP5:  INTA:=UP[5];
      'FOR' N:=0,1,2,4 'DO'
      'BEGIN'
      TRAVEL1;  DISX[N]:=GAPX+DISX[N];
            INTER4(U,UP,UX,UY,X,Y);
            INTER4(V,VP,VX,VY,X,Y);
            INTER4(A,AP,AX,AY,X,Y);
      'END';
      SOLVE3;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-UP[5])/UP[5])>0.001 'THEN' 'GOTO' LOOP5;
      'END';
      'IF' CASE[X,Y]=81 'THEN'
      'BEGIN'  AP[5]:=AC[T+1];
LOOP6: INTA:=VP[5];
      'FOR' N:=0,1,3,4 'DO'
      'BEGIN'
      TRAVEL1;  DISY[N]:=-GAPY+DISY[N];
            INTER4(U,UP,UX,UY,X,Y);
            INTER4(V,VP,VX,VY,X,Y);
            INTER4(A,AP,AX,AY,X,Y);
      'END';
      SOLVE3;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-VP[5])/VP[5])>0.001 'THEN' 'GOTO' LOOP6;
      'END';
      'IF' CASE[X,Y]=78 'THEN'
      'BEGIN' AP[5]:=AC[T+1];
LOOP4:  INTA:=UP[5];
      'FOR' N:=0,1,4 'DO'
      'BEGIN'
      TRAVEL1;  DISX[N]:=GAPX+DISX[N]; DISY[N]:=-GAPY+DISY[N];
            INTER4(U,UP,UX,UY,X,Y);
            INTER4(V,VP,VX,VY,X,Y);
            INTER4(A,AP,AX,AY,X,Y);
      'END';
      SOLVE78;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-UP[5])/UP[5])>0.001 'THEN' 'GOTO' LOOP4;
      'END';
      'IF' CASE[X,Y]=8 'THEN'
      'BEGIN'  AP[5]:=AC[T+1];
LOOP8: INTA:=VP[5];
      'FOR' N:=0,1,3,4 'DO'
      'BEGIN'
      TRAVEL1; DISY[N]:=-GAPY+DISY[N];
            INTER4(U,UP,UX,UY,X,Y);
            INTER4(V,VP,VX,VY,X,Y);
            INTER4(A,AP,AX,AY,X,Y);
      'END';
      SOLVE3;
      COUNT:=COUNT+1;
      'IF' ABS((INTA-VP[5])/VP[5])>0.001 'THEN' 'GOTO' LOOP8;
      'END';
;
       'IF' T=TLIM-1 'THEN' 'BEGIN'
      PRINT(X,3,0);
      SPACES(3);
      PRINT(Y,3,0);
      SPACES(5);
      PRINT(UP[5],0,8);
      SPACES(4);
      PRINT(VP[5],0,8);
      SPACES(4);
      PRINT(AP[5],0,5);
      NEWLINES(1);
      'END';
      U[X,Y,1]:=UP[5]; V[X,Y,1]:=VP[5]; A[X,Y,1]:=AP[5];
      'IF' Y<YLIM 'THEN' 'BEGIN' Y:=Y+1; 'GOTO' BACK2; 'END';
      'IF' X<XLIM 'THEN''BEGIN' Y:=1; X:=X+1; 'GOTO' BACK2; 'END';
      'FOR' Y:=1 'STEP' 1 'UNTIL' YLIM 'DO'
      'BEGIN'
      'FOR' X:=1 'STEP' 1 'UNTIL' XLIM 'DO'
      'BEGIN'  U[X,Y,0]:=U[X,Y,1];
              V[X,Y,0]:=V[X,Y,1];
              A[X,Y,0]:=A[X,Y,1];
      'END'; 'END';
      T:=T+1;
      'IF' T<TLIM 'THEN' 'GOTO' BACK1;
'END';
'END'
 'END';
//RUN
4;4;15;0.333;0.333;0.0333;
0;-0.0001;5;81;0;-0.0001;5;1;0;-0.0001;
5;1;0;0;5;12;
0.0001;-0.0001;5;8;0.0001;-0.001;5;0;
0.0001;-0.0001;5;0;
0.0001;0;5;2;
0.0001;-0.0001;5;8;0.0001;-0.001;5;0;0.0001;-0.0001;5;0;
0.0001;0;5;2;
0.0001;-0.0001;5;78;0.0001;-0.0001;5;7;0.0001;-0.0001;5;7;
0.0001;0;5;27;
0.2;10;32.2;0.45;62.4;0.5;
5.00;4.95;0;