BEGIN
    INTEGER NUM_PARTICLES;
    INTEGER LINES, COLUMNS;
    INTEGER SEED;

    NUM_PARTICLES := 1000;
    LINES := 46;
    COLUMNS := 80;
    SEED := ININT;
    BEGIN

        PROCEDURE DRAW_BROWNIAN_TREE(WORLD); INTEGER ARRAY WORLD;
        BEGIN
            INTEGER PX, PY;  COMMENT PARTICLE VALUES ;
            INTEGER DX, DY;  COMMENT OFFSETS ;
            INTEGER I;

            COMMENT SET THE SEED ;
            PX := RANDINT(0,LINES-1,SEED);
            PY := RANDINT(0,COLUMNS-1,SEED);
            WORLD(PX,PY) := 1;

            FOR I := 0 STEP 1 UNTIL NUM_PARTICLES - 1 DO BEGIN
                COMMENT SET PARTICLE'S INITIAL POSITION ;
                PX := RANDINT(0,LINES-1,SEED);
                PY := RANDINT(0,COLUMNS-1,SEED);

                WHILE TRUE DO BEGIN
                    COMMENT RANDOMLY CHOOSE A DIRECTION ;
                    DX := RANDINT(-1,1,SEED);
                    DY := RANDINT(-1,1,SEED);

                    IF DX + PX < 0 OR DX + PX >= LINES
                    OR DY + PY < 0 OR DY + PY >= COLUMNS THEN
                    BEGIN
                        COMMENT PLOP THE PARTICLE INTO SOME OTHER RANDOM LOCATION ;
                        PX := RANDINT(0,LINES-1,SEED);
                        PY := RANDINT(0,COLUMNS-1,SEED);
                    END ELSE IF WORLD(PX + DX, PY + DY) <> 0 THEN BEGIN
                        COMMENT BUMPED INTO SOMETHING ;
                        WORLD(PX, PY) := 1;
                        GO TO BREAK;
                    END ELSE BEGIN
                        PY := PY + DY;
                        PX := PX + DX;
                    END IF;
                END WHILE;
                BREAK:
            END FOR;
        END DRAW_BROWNIAN_TREE;

        INTEGER ARRAY WORLD(0:LINES-1,0:COLUMNS-1);
        INTEGER I,J;

        DRAW_BROWNIAN_TREE(WORLD);

        FOR I := 0 STEP 1 UNTIL LINES-1 DO
        BEGIN
            FOR J := 0 STEP 1 UNTIL COLUMNS-1 DO
            BEGIN
                OUTCHAR(IF WORLD(I,J)=0 THEN '.' ELSE '*');
            END;
            OUTIMAGE;
        END;

    END;
END.