SINCLAIR PROGRAMS, July/August 1982
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ZX81 Games

COVER THE BOX (16K ZX-81)
DOCKING (1K ZX-81)
DRAGON CRUNCH (1K ZX-81)
DUEL (1K ZX-81)
FIRE ESCAPE (1K ZX-81)
GOLF (16K ZX-81)
GRUB RACE for Sinclair ZX-81
HOLED UP (Alien Lure) for Sinclair ZX-81
KNIGHT'S MOVE (16K ZX-81)
MEMORY (1K ZX-81)
OCTOPUS (1K ZX-81)
OWZAT (1K ZX-81)
PEARL DIVER (1K ZX-81)
PIGEON RACE (16K ZX-81)
PONTOON (16K ZX-81)
SHIPS (1K ZX-81)
SOLITAIRE (16K ZX-81)
STAR SMASH (1K ZX-81)
STUNT RIDER (1K ZX-81)
TRAIN BLOCK (1K ZX-81)
TREASURE HUNTER (1K ZX-81)
TUG (1K ZX-81)
WIPE OUT (1K ZX-81)
ZOMBIES (16K ZX-81)


COVER THE BOX (16K ZX-81)
by John Ellis
from Sinclair Programs 2, July-August 1982, page 42

A good, interesting game, which takes slightly less than 3K of memory on the
ZX-81 is sent by John Ellis, of Wimborne, Dorset. He says it is based on an
old French game known as Shut the Box.

The aim is to eliminate each of the numbers from one to nine by throwing two
dice. The total thrown can then be used to eliminate numbers which add to the
same total. For example, if a three and a five are thrown, any combination of
two numbers adding to eight can be eliminated.

The chosen numbers are entered together and the program checks for illegal
moves. The game continues until it is impossible to make a move; no number
can be eliminated twice. To end the game, press zero and the total of the
numbers remaining is displayed. After a number of plays a running average of
the remaining totals is shown; Ellis says that after much practice his
average for 10 games was 8.3. The program is user-friendly.


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DOCKING (1K ZX-81)
by J Smith
from Sinclair Programs 2 (July/August 1982), page 31

Docking, from J Smith of Coulsdon, Surrey, is like many of the Lunar Lander
types of games where a craft has to be maneuvered to land safely. The added
spice to this version is that, in the words of its creator, "the space
station is infested with 'space virus' which creates havoc and sends people
mad. The station therefore is out of control".

The landing must be made as the station is moving about the screen in a
random fashion with a limited amount of fuel remaining.

As usual, movement is controlled by the cursor keys and if a safe landing is
achieved the number of moves taken is recorded.


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DRAGON CRUNCH (1K ZX-81)
by D G Hockey
from Sinclair Programs 2 (July/August 1982), page 9

Despite the short history of Sinclair Programs and its companion publication,
Sinclair User, we are already spawning new ideas. The inspiration for Dragon
Crunch from D G Hockey of London, E18 was Tim Hartnell's Monster Munch, which
appeared in the May edition of Sinclair User.

Hockey thinks that this version is better, because it lasts longer and fits
into the 1K ZX-81 by using a number of memory-saving devices.

To move the figure which is being chased by the dragon, it is necessary to
enter two letters, such as W for west and NE for north-east but that is not
too much of a problem.

When the dragon eventually catches you the number of moves taken is shown.
Hockey says that the maximum achieved by his family was 48.


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DUEL (1K ZX-81)
by Mark Beard
from Sinclair Programs 2 (July/August 1982), page 34

Despite the two guns in this game looking like machine-guns, they only fire
one at a time. They are even gentlemanly about refusing to fire a shot until
the previous shot has either missed or found its target.

The duel is fought against the computer, which seems to have an uncanny sense
of when to shoot. The player has to put the gun into the correct position by
using D for moving up, G for down and F to fire.

Duel, which can fit on to the 1K ZX-81, was sent by Mark Beard of Hilsea,
Portsmouth.


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FIRE ESCAPE (1K ZX-81)
by Roy Hair
from Sinclair Programs 2 (July/August 1982), page 28

Fire Escape, which can fit into 1K ZX-81, is a variation of the catcher type
of game. When run, a block of flats is simulated on the left-hand side of the
screen from which a figure, denoted by a bracket, jumps, and the object is to
catch the figure before it hits the ground.

The catching blanket is moved from side to side by the cursor keys 5 and 8.

The game is made more interesting and difficult by a 'wind' moving the figure
in the air, which makes constant adjustment of the blanket necessary. The
concentration needed to do it makes it difficult to play the game for long,
as the flashing of the figures hurts the eyes after a time.

After 10 people have jumped, your score, showing how many you saved, is shown
and you can start the game again.

Fire Escape was sent by Roy Hair, of Kilmarnock, Scotland.


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GOLF (16K ZX-81)
by R A Lean
from Sinclair Programs 2 (July-August 1982), pages 32-33

On the rare occasions when the weather is too bad to play Gold, fanatics may
care to try the computer version. It requires the 16K RAM pack and can be as
frustrating as the real thing - but not so tiring or expensive.

For each of nine holes the program selects a random distance between 200 and
400 yards and displays it with the par value. The player is invited to play
strokes at strengths from one to nine and after each stroke the distance
remaining is displayed, with the number of strokes taken at the hole, a further
request to choose a shot.

That continues until the ball is in the hole, when the comparison with par is shown.

At the end of the nine holes the par for the course is shown, with the score
for that game and some advice about the future of your game.

The numbers for strength of shot do not correpond to the numbers of real clubs.
The best guide to the distance which can be expected can be obtained from lines
90 to 98. Although each distance is chosen at random, they are in the region of
the last figures. The exception is shot one, which always moves the ball one yard.

That ranmdom element is the cause of the frustration, particularly when the
ball is less than four yards from the hole. The choice must always be between
taking the safe method and playing a series of one-yard shots, and the two,
which can give two, three or four yards.

With a little concentration, a good level of skill can be achieved and you can
avoid being told to sell your clubs at the end of the nine holes.

Golf was sent by R A Lean of St Austell, Cornwall.


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GRUB RACE for Sinclair ZX-81
by Roy Kay
from Sinclair Programs, July/August 1982

Grub Race involves a race between three good representations of caterpillars.
The progress of the race is decided by random elements in the program and the
player places bets on the likely winner, starting with a total of #100.

The race is complicated by the fact that at any moment the cater- pillars may
turn into butterflies which, after fluttering on the screen for a time,
return to being caterpillars and have to start again. Complete instructions
are included in the program once it is run.

The graphics in lines 60, 70 and 80 are 30 shifted Ss and two shifted As and
the butterflies in line 1061, 1071 and 1081 include two shifted As.

Grub Race was sent by Roy Kay of Wirral, Merseyside and requires a RAM pack.


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HOLED UP (Alien Lure) for Sinclair ZX-81
by Sanath Yogasundrum
from Sinclair Programs, July/August 1982

A game which links the bug-baiting type of program with a battle against
alien invaders has been produced by Sanath Yogasundrum of Ashton, Preston,
Lancashire.

When the game begins the player is asked for a skill level, A or P, which
stand for amateur or professional. It is advisable to start on the amateur
level while the player begins to understand this complex game.

A small grid is shown in the bottom left-hand corner of the screen in which
there are four aliens, shown as X and $, with a soldier (*). The soldier has
to dig a hole (O) and then lure the aliens into it, scoring 100 points for
every X and 200 for every $.

The hole is dug by going into dig more - pressing 2 - and pressing the cursor
key for which side of the soldier you wish to place the hole. The soldier can
then be moved by pressing 1 to return to movement mode, and using the cursors
in their normal directions.

A soldier can be killed either by falling into his own hole or being eaten by
an alien. The game lasts for the lives of three soldiers, although an extra
soldier can be gained by scoring more than 3,000.

Two other limitations are that only one hole can be dug at a time and a hole
cannot be dug beneath an alien. Once an alien has fallen into a hole it is
filled immediately and the game continues.

Even after playing for more than an hour at the amateur level, no-one at
Sinclair Programs managed to score more than 1,300.


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KNIGHT'S MOVE (16K ZX-81)
by K M Godolphin
from Sinclair Programs 2 (July/August 1982), page 29

Knight's Move uses the movement pattern of the Knight in chess to try to
cover every space in a square. The program asks where you wish to start on
the board, giving the vertical co-ordinate first, and then marks the moves as
you make your way round the board.

There is a check routine to make sure you cannot cheat by making an incorrect
move or land more than once on the same square. When no more squares can be
visited, enter 0 as the number for the next square.

Press NEW LINE to replay the game or any othe key and NEW LINE to end the game.

Knight's Move was sent by K M Godolphin, of Camborne, Cornwall, and needs 16K RAM.

[The program suffers from a bug that does not prevent all illegal moves.

These lines:

   370 IF L=L1-2 OR L=L1+2 AND C=C1-1 OR C=C1+1 THEN GOTO 220
   380 IF L=L1-1 OR L=L1+1 AND C=C1-2 OR C=C1+2 THEN GOTO 220

should be as follows:

   370 IF (L=L1-2 OR L=L1+2) AND (C=C1-1 OR C=C1+1) THEN GOTO 220
   380 IF (L=L1-1 OR L=L1+1) AND (C=C1-2 OR C=C1+2) THEN GOTO 220
]


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MEMORY (1K ZX-81)
by C J Barnatt
from Sinclair Programs 2 (July/August 1982), page 28

As its name suggests, Memory is a game for remembering things. When run, a
series of 10 random characters, both letters and numbers, is displayed for
about four seconds. The screen then goes blank, during which time you have to
enter as many characters as you can remember.

After another six seconds, the characters which you did not type-in are
displayed on the screen.

The game can then be repeated by pressing RUN and NEW LINE, when another
series of characters appears.

It is a simple but absorbing game which can be played for hours. It was sent
by C J Barnatt, of Fernhill Heath, Worcester.


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OCTOPUS (1K ZX-81)
from Sinclair Programs 2 (July/August 1982), page 8

There are memories of Captain Nemo and the Nautilus in the game of Octopus. A
submarine is being chased by the octopus - which unfortunately looks more
like a crab - and it is only a question of time before it is caught.

As the game progresses, the speed of the submarine falls but that of the
octopus does not. The aim is to stay out of the grips of the octopus for as
long as possible. The submarine is maneuvered using the normal cursor keys.

After several attempts, the Sinclair Programs reviewer managed a score of 109.

As an added interest, when the octopus hits the top of the screen the lines
comprising it are reversed, giving the impression that it is standing on its
hands.

Octopus was sent by Colin Macdonald, of Gourock, Renfrewshire.


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OWZAT (1K ZX-81)
by Nick Gray
from Sinclair Programs 2 (July/August 1982), page 40

A simple game based on the famous cricket dice game, Owzat, simulates a
simple form of the complex summer game. Once running, it runs automatically
through until a team of 10 has completed its innings and gives the total
score. The game is repeated to find the score of the opponents.

One problem which readers might like to tackle is to find a way of removing
Owzat and not out once an appeal has been turned down. Because of this it is
not known when another appeal has been made until one is allowed and the next
batsman's score is shown.

Owzat fits into 1K ZX-81 and was sent by Nick Gray of Burton-on-Trent,
Staffordshire.


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PEARL DIVER (1K ZX-81)
by G Layton
from Sinclair Programs 2 (July/August 1982), page 24

Pearl Diver will fit on the 1K ZX-81 and, as the name suggests, involves a
diver attempting to pick up a pearl before he runs of air.

The diver moves automatically across the screen from left to right and is
moved up and down by the cursor keys 6 and 7. When the warning is given that
the diver is running out of air the player has the choice of continuing to
try to catch the pearl before he drowns or returning to the surface.

At the end of the game, the number of pearls collected is shown.

Pearl Diver was sent by G Layton, of Gaydon, Warwickshire.


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PIGEON RACE (16K ZX-81)
by Roy Kay
from Sinclair Programs 2 (July-August 1982), pages 38-39

If you want a program to send you mad, Pigeon Race must be one of the
contenders. It simulates a pigeon race with a set of three somewhat erratic
pigeons which any self-respecting fancier would probably have put out of their
misery long ago.

The object is to start with 100 and make more by backing the winning pigeon in
each race. According to the write, Roy Kay, of New Ferry, Wirral, Mereyside, it
is possible to be successful with a little intuition and a good deal of luck.
The emphasis is on the luck.

The pigeons start the game at the bottom of the screen and are put to flight by
the player first entering the bird which he will back and then the size of the
bet. The game ends when one of the drunken birds arrives at the corresponding
coop at the top of the screen.

Because of the random element, some races can finish in a few seconds, while
others seem to continue all day.

The game needs 16K to work.


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PONTOON (16K ZX-81)
by Paul Mapstone
from Sinclair Programs 2 (July-August 1982), pages 15-16

This version of the card game Pontoon requires a minimum of 4K RAM on the
ZX-81. The program is a very good simulation of the game which is played with
the computer as the dealer.

S is pressed for stick and T for twist, with the answer as to whether you wish
to play again after the end of a game being a Y or N. No betting is involved -
only the satisfaction of having beaten the computer.

Pontoon was sent by Paul Mapstone, of London N7.


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SHIPS (1K ZX-81)
by Ian Johnston
from Sinclair Programs 2 (July/August 1982), page 23

For the 1K ZX-81, Ships is a simple type of missile game in which a target
moves at various distances from the gun across the screen and the objective
is to hit it. Ten ships pass and the score is shown at the end of each game.

Only one shot can be made at a time, so the skill is in judging when to fire,
so that the missile and ship coincide. When a hit is made in the middle of
the ship, BANG is shown on the screen.

Press RUN and NEWLINE to start each game and P to fire the missile. The
Sinclair Programs reviewer managed a top score of four.

Ships was sent by Ian Johnston, of Newmarket, Suffolk.


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SOLITAIRE (16K ZX-81)
by Frank Webster
from Sinclair Programs 2 (July-August 1982), page 47

This is a 16K ZX-81 representation of the popular game of Solitaire, where the
game begins with a number of pegs in a cross formation and one missing in the
middle. The object is the clear the pegs by jumping over them and leaving one
peg in the middle hole.

In this version, from Frank Webster, of West Kirby, Wirral, Merseyside, the
pegs are shown by Os and the holes by stars. The board has vertical and
horizontal coordinates and a move is made by entering the description of the
page being moved, with the vertical figure first and the desciption of the hole
to which it is being moved, and pressing NEWLINE.

The program eliminates cheating by recognising invalid moves. When a player can
no longer move the F key is pressed to end the game.


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STAR SMASH (1K ZX-81)
by Adam Hobden
from Sinclair Programs 2 (July/August 1982), page 10

Star Smash is similar to the slalom games except that the object is not to
avoid the obstacles moving towards you but to hit as many as possible. The
ship is moved from side to side by the cursor keys 5 and 8. After a given
time a score is shown.

The game can be re-started by pressing RUN and NEWLINE.

Star Smash can be fitted on to the 1K ZX-81.


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STUNT RIDER (1K ZX-81)
by Paul Richards
from Sinclair Programs 2 (July/August 1982), page 30

Stunt Rider simulates a motor-cyclist of the Evil Knievel variety jumping a
series of barrels. The J key is pressed to jump and if it is not held down
long enough the cyclist falls into the barrels, bringing a CRASH on the
screen.

It is a very simple programs. It does not take long to enter and can provide
some enjoyment.

Stunt Rider was sent by Paul Richards, of Swindon, Wiltshire.


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TRAIN BLOCK (1K ZX-81)
by Ian Johnston
from Sinclair Programs 2 (July/August 1982), page 14

A simple game with some ingenious graphics has been produced by Ian Johnston,
of Newmarket, Suffolk.

A train moves across the screen from left to right and the object is to block
it, using a large buffer on the right-hand side of the screen. The train
arrives at varying heights and the buffer must be moved up and down to stop
it, using the Q for up and the A for down. When the train nears the buffer it
is necessary to press P to stop it.

Each time a train is blocked, one is added to the score, which is shown on
the buffer. The game ends when three trains have passed the buffer.


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TREASURE HUNTER (1K ZX-81)
by P Brown
from Sinclair Programs 2 (July/August 1982), page 19

Treasure Hunter is a clever little game in which a hunter, denoted by an
asterisk, has to find treasure which is hidden at a random position on
screen. The only assistance given to the hunter is that he is told when he is
getting warmer.

It can be very annoying when, whichever way you move, you seem to be getting
warmer but cannot find the exact location of the treasure. When the correct
spot is found, the number of steps taken is shown on the screen, along with
the program's idea of the optimum number.

The first attempt by the Sinclair Programs reviewer results in 453 steps
taken against an optimum of five. That later improved to 84 against an
optimum of 30.

The hunter is moved by using the cursor keys but an added difficulty is that
if you go to the edge of the screen you bounce back so that the left and
right keys and the up and down keys can become reversed.

Treasure Hunter was sent by P Brown of Charlesworth, Derbyshire.


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TUG (1K ZX-81)
by Peter Brett
from Sinclair Programs 2 (July/August 1982), page 37

The aim of Tug is to make as high as score as possible before a line which
moves from right to left across the screen reaches the end. To stop the line
moving it is necessary to match a random number which appears on the screen.
Each incorrect answer allows the line to advance.

The program has nine skill levels, running from one to nine, with nine being
the easiest. The most difficult is almost impossible, as the time allowed for
entering the number is so short.

Tug will fit into the 1K ZX-81 and was sent by Peter Brett, of Swindon,
Wiltshire.


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WIPE OUT (1K ZX-81)
by Keith Paterson
from Sinclair Programs 2 (July/August 1982), page 23

A deceptively simple but frustrating game has been sent by Keith Paterson of
Newmarket, Suffolk. When run, two walls are displayed with an O between them.
The O can be used to eliminate the walls but as it does so it leaves a trail
of Os behind it when moving vertically. No trail is left when moving
horizontally.

The object is to finish with only one O on the screen. Despite a lengthy
attempt by the Sinclair Programs reviewer, that proved impossible but
Paterson maintains that it can be done with a little thought and
concentration.

The O is moved by the cursor keys in the usual directions. It can be run on
the 1K ZX-81.


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ZOMBIES (16K ZX-81)
by Christopher Smith
from Sinclair Programs 2 (July-August 1982), page 45

Zombies is a version of the lure type of game where a number of attackers
converge on a target. As they approach it they can hit various obstacles. The
attackers are Zombies, shown as Zs chasing the players, an X, with potholes,
Os, as obstacles.

The difference between this and other games is that there is a random number of
Zombies chasing the player.

When z Zombie falls into a pothole, the event is marked by an announcement on
the screen "Splash goes a Zombie". Should you lure all of them to their doom
you are told, cheerily, that you may have won on that occasion but you cannot
win in the end.

When a Zombie strikes you the screen is filled with sickening munches, gobbles
and burps. You can move in any direction by following the positioning of
numbers shown in a box beneath the game display.

Zombies was sent by Christopher Smith, of Christchurch, Dorset and requires the
addition of a RAM pack.
