THIS IS THE GAME OF TETRIS, FIRST WRITTEN BY TWO GUYS FROM RUSSIA.

ADAPTED TO THE VAX WORLD BY:
        DAVID BRYANT
        COLUMBIA, MD

THE OBJECT IS TO MOVE AND ROTATE DROPPING OBJECTS SO AS TO
CREATE COMPLETE ROWS.  WHEN A ROW IS COMPLETE IT IS REMOVED AND
ALL THE OBJECTS ABOVE IT DROP DOWN ONE LEVEL.

TETRIS KEYBOARD:

        RIGHT AND LEFT ARROW KEYS        MOVE OBJECT SIDE TO SIDE
        "S" KEY                          ROTATE OBJECT COUNTER-CLOCKWISE
        "D" KEY                          ROTATE OBJECT CLOCKWISE
        PF1 KEY                          START GAME
        PF2 KEY                          PAUSE GAME HIT PF2 TO CONTINUE
        PF3 KEY                          PAUSE GAME AND CLEAR SCREEN
                                         HIT PF3 TO CONTINUE
        PF4 KEY                          EXIT GAME AND CLEAR SCREEN

AT THE END OF A ROUND, THE SCREEN IS CLEARED AND YOU BEGIN FRESH.
A ROUND IS COMPLETED BY FILLING THE SPECIFIED NUMBER OF ROWS BEFORE
THE GAME ENDS.  THERE ARE THREE SPEEDS AT WHICH THE OBJECTS DROP.
THE SLOWEST SPEED LASTS FOR THE FIRST TWO ROUNDS.  THE MEDIUM SPEED
LASTS FOR THE NEXT TWO ROUNDS AND THE FASTEST SPEED FOR THE REMAINDER
OF THE GAME.

POINTS ARE AWARDED IN THREE CASES.
        1)  AN OBJECT REACHES THE FLOOR.
        2)  A ROW IS FILLED.
        3)  A ROUND IS COMPLETED.

THE HIGH SCORE IS KEPT IN A FILE KNOWN BY THE LOGICAL TETRIS$HIGH_SCORE.
THIS LOGICAL MUST BE SET FOR TETRIS TO LOG THE HIGH SCORE.
    EXAMPLE:
        $DEFINE TETRIS$HIGH_SCORE MY$DISK:[MYDIR.TETRIS]HIGH_SCORE.DAT

NOTE:  ON VT100 TERMINALS, YOU MUST SET THE CURSOR TO UNDERLINE TO SEE
       THE OBJECTS CORRECTLY.

ANOTHER NOTE:  BECAUSE OF SMG$ PROBLEMS, KEYSTROKES MAY GET CAUGHT IN THE
               TYPE-AHEAD BUFFER IF YOU PRESS THE KEYS TOO QUICKLY.
               TO FIX THIS, PRESS CTRL-A, THEN HIT RETURN.