
PHASOR
by Marcus Harvey
from Sinclair User 9 (Dec.1982)


Remarkable graphics effects are the striking features of Phasor for the
16K ZX-81. You are an infamous space pirate travelling home through
hyperspace after a hard day's murder and mayhem. Suddenly you find your-
self wrenched back into real space/time by a squadron of Federation
star-ships. You are hopelessly surrounded. Can you fight your last
battle with style?

The view from your cockpit is of stars and galaxies in the blackness of
space. Each attacking star-ship is an inverse 0 appearing at random
positions around the screen. You are required to note in which column it
appears, relate that to the letters at the bottom of the display and hit
the appropriate key on the ZX-81. If you miss, or delay too long, your
assailant will take up position at screen centre and loose a series of
devastating thermal bolts at your ship.

That is where the original graphics come in. The two energy beams from
the Federation ship approach with a striking 3D effect. If they are on
target, they rock your pirate ship by means of the FAST/SLOW loop in
lines 1200 to 1240. Excellent.

You cannot fire at the ship when it is firing at you. You must destroy
15 ships to qualify for a new screen and the game speeds up as each
screen is cleared. If you break into the program, remember to re-start
it with "RUN 2", since the program saves itself in line 1.

A series of honorary accolades is awarded for a high score. Anything
above 1,050 gains the accolade of Starfalcon, Starhawk or Stareagle,
depending on the level of difficulty selected. You will have to be good,
though, since the author of the program, Marcus Harvey of Surbiton,
Surrey, has managed a personal best of only 550.



TAPE READER for Sinclair ZX-81
by C M Woodman
from Sinclair User, December 1982

[It supports filenames up to 20 characters long. JimG]

Tape Reader is a useful routine to add to your ZX-81 software library.
The bulk of the program is a machine code routine written into one line.
It will read through a tape of programs and list the names of programs
on that tape as it proceeds.

Run the program to set up the machine code and then delete lines 5 to 60.
The program is then ready to run.

Instead of typing LOAD "" before starting your cassette recorder type
RUN 100 to start the reader program. Then start the tape.


--
Another Fine Product transcribed by:
Jim Grimwood, Weardale, England (http://www.users.globalnet.co.uk/~jg27paw4/)
--



HAMPSON'S PLANE (ZX-81)
by I Turtle
from Sinclair User 9 (September 1982), page 61

Hampson's Plane for the 16K ZX-81 is derived from an attempt to simulate in
two dimensions as many features of Rubic's Cube as possible., The author of
the listing, I Turtle of Scunthorpe, South Humberside. discoverd the basic
idea from an article in an American magazine.

The rules of the game are fairly simple. The screen is covered by 20 lines of
plus signs. The computer, running in FAST mode, selects one of the symbols at
random and inverts it and its eight immediate neighbours. The process is
repeated a number of times, depending on the skill level.

When the computer has finsihed, your job is to convert the screen to normal,
using the same technique, i.e., defining the centre square of a group and
ordering the machine to invert it and its neighours. The move should be input
as "Letter, number, NEWLINE".



NOTE TESTER (ZX-81)
by A J Robinson
from Sinclair User 9 (September 1982), page 65

If you do not know your notes but want to learn, Note Tester from A J
Robinson of Monks Risborough, Bucks for the 1K ZX-81 is bound to help. The
display features a treble stave and a blob at some random position on it. The
blob represent a musical note which you have to guess, or know.

The computer will tell you whether you are correct and will then wait for you
to press any key before RUNning once again.

Listing buffs might like the way the random number is linked to the note
through CHR$.



STANDARD DEVIATION (ZX-81)
by David Lam
from Sinclair User 9 (September 1982), page 66

Standard Deviation is a measure used in statistics of the scatter of a series
of numbers or measurements around their mean value. The program for the ZX-81
from David Lam, of London NW10, is a method of calculating both standard
deviation and the arithmetical mean.



LONDON BRIDGE (ZX-81)
by J K Laskowski
from Sinclair User 9 (September 1982), page 67

Most computer games require nothing except a quick finger on the cursor key.
Most of the rest, those which require a bit of brain power, are adaptations
of games when the word computer meant a Chinese woman with an abacus.

London Bridge is one of the few routines we have seen which is original, was
written for the computer, and which calls for nerve, thought and luck.

The display consists of a graphic representation of the bridge, seen from
above, with the roadway made up of a random mix of the numbers 1 to 5,
representing five types of flag-stone. You are required to cross to the other
bank but, as you would expect, London Bridge is falling down.

The computer will gove you a number, perhaps 4. That tells you that one of
the type 4 stones is about to fall into the river. In selecting your next
move, therefore, you can gamble by moving on to a 4 or play safe by selecting
a different number.

The player enters his move by following the nine-number grid displayed under
"INPUT" in the bottom left of the screen; 7, for example, will move you left
and down and 2 will send you directly backwards.

Invalid moves are ignored. You score 10, 20 or 50 points respectively for
each move forwards, sideways or backwards, but taking risks trebles those
scores and a high score is necessary to beat the world record of 1,700.
Beware - don't dally too long at the start of the bridge - you may be cut off
by successive collapses, and don't shilly-shally near the south bank because
that is where the bridge is weakest.

We were very impressed by the program and counted ourselves lucky to manage a
score of 1,900 after 12 attempts. Congratulations to J K Laskowski of London
SE6 for an impressive listing for the 16K ZX-81.

