v1.0, Copyright 1991, Bob Lancaster
Crux is a colorful puzzle/game in which players try to achieve high
score by placing multicolored cross-shaped pieces (cruxes) on a
grid so that only crux-arms of the same color are touching. The
more arms that match a newly played crux, the more points you get!
Think of it as four-sided, color-coded dominoes!
Each round gives you more colors to contend with, making things a
bit trickier as the game progresses.
The word "crux" is Latin for "cross", but in English also means "a
puzzling or difficult problem". Getting it so that the last pieces
to fit on the grid can be just that!
Crux will run on any IBM PC/AT/XT/PS2 or close clone thereof, with
at least 100k of memory available after DOS is loaded.
Although the game looks best when played on a color monitor, it
will work on a monochrome. (If you are using a monochrome or
composite monitor with a color graphics card, please see "Black And
White Mode" in the Command Line Parameters section below)
A Microsoft-compatible mouse can be used. (Remember to load your
mouse driver before starting Crux).
If you run across a configuration on which the game will not run,
please let me know (address at end of this file)!
Microsoft Mouse Support
Monochrome/Composite monitor support
Top Ten Scores file
Statistics on multiple games
Optional PC Opponent
Screen Blanker during play
In Crux, you start each round with an empty grid of cross-shaped
You are dealt a hand of four-armed, cross-shaped pieces (called
"cruxes") to place on the grid. Figure 1 shows a crux, with two
red arms, one blue arm, and one yellow arm (For purposes of this
documentation, RR=Red, BB=Blue, YY=Yellow and GG= Green).
| YY |
| RR RR |
| BB |
Figure 1 (A crux)
Each Crux is played in the following manner:
1) Using the Home/End keys (or the mouse left button), you
choose a crux from the hand.
2) Using the cursor keys (or the mouse left button), you choose
a location for the crux.
3) Using the Page Up/Down keys (or the right mouse button), you
rotate it so that it is aligned the way you wish.
4) Pressing enter locks the crux in place.
Cruxes may be placed in any empty space on the grid, as long as
each of its four arms are NOT touching a different-colored arm of
another crux. If a crux's arms aren't touching ANY other crux, the
move is confirmed, to prevent accidental zero-point moves.
Here's an example: Figure 2 shows a portion of the grid after some
cruxes have been played. Note that all arms that are touching are
of the same color (RR=Red, BB=Blue, GG=Green, YY=Yellow).
| RR YY .. .. YY |
| RR BB BB YY .. .. .. .. GG GG |
| GG RR .. .. BB |
| .. RR .. .. .. |
| .. .. GG YY .. .. .. .. .. .. |
| .. BB .. .. .. |
Figure 2 (Portion of grid during play)
Figure 3 shows a new crux to be placed on the grid, with two green
arms, a blue and a red arm.
| RR |
| GG BB |
| GG |
Figure 3 (New crux to be played)
In Figure 4, two possible plays are shown (in lower case). Notice
how the crux had to be rotated in order that the colors on its arms
matched those of neighboring cruxes.
| RR YY .. .. YY |
| RR BB BB YY .. .. .. .. GG GG |
| GG RR .. .. BB |
| gg RR .. .. bb |
| bb gg GG YY .. .. .. .. rr gg |
| rr BB .. .. gg |
Figure 4 (Some possible plays)
Notice that the possible play in the lower left corner of Figure 4
has two arms which match those of its neighbors, while the one in
the lower right hand side only matches one.
When you place a crux, the more of its arms which are touching
like-colored arms of other cruxes, the more points you earn (see
After playing each crux, the used crux is replaced in your hand.
Pay attention to the Hand window, and think ahead! This will allow
you to place the current crux in such a way to take best advantage
of the others you can see.
The number of points earned for placing a crux depends on two
- How many matching (like-colored) arms it touches.
- What round is being played.
The later rounds give you more colors to contend with, making
matching more and more difficult, and so more points are earned.
| Round number 1 | 2 | 3 |
| Cruxes in hand 3 | 4 | 5 |
| Number of colors used 3 | 4 | 5 |
| Points for 1-way match 1 | 2 | 3 |
| 2-way match 3 | 6 | 9 |
| 3-way match 10 | 20 | 30 |
| 4-way match 30 | 60 | 90 |
| Bonus for filling grid 50 | 100 | 150 |
A player's turn is over when he or she has either filled the grid,
or cannot find a legal place to play a given crux.
After three rounds, the player with the highest score is the winner!
STARTING THE GAME
At this point, you should be able to play the game, and get a feel
for it. You can read the rest of this document now at your leisure
to clarify points, and to explain some of the features you might
not understand your first few times through the game.
So, make sure you are in DOS, and type "MLCRUX" (without the
quotes) and press return. Follow the prompts, and enjoy!
Crux can be played either using the keyboard or a Microsoft-
The legend (the last line on the screen) always contains a list
of keys that are valid at any point in the game, usually along
with a one-word description of their function. (See "COMMANDS"
Most of the keys listed on the bottom line of the screen can be
entered via the mouse by pointing to the command and clicking
the left button of the mouse. (If you are new to mice,
"clicking" something means to place the mouse cursor on it and
press the appropriate button, in this case, the left.)
When selecting a crux from your hand, left-click the crux in the
When placing a crux, left-click the grid location where you
want to place the crux. Clicking the right mouse button will
rotate the crux clockwise. Once the crux is properly aligned,
clicking it a second time with the left mouse button finishes
Also, boxes higher on the screen with messages such as "Press
return for next player" will allow you to click the box itself
to continue, rather than the command at the bottom of the
So, experiment with the mouse, and see what works. I think it's
fairly straightforward, but would appreciate any feedback on
ways you think it could be improved (address at end of file).
COMMANDS AND TOGGLES
A number of commands and toggles are available to enhance play, or
to allow you to tailor the game a little to suit your taste.
Alphabetically, these are:
A (AllScores command)
This displays a scorecard of all players, to compare how
everyone is doing in relation to each other. The highest
score(s) are emphasized with a flashing arrow.
B (BossKey command)
This displays a phony DOS screen. I'll explain for you honest
folks: this key is used when you are playing the game on company
time, and the boss suddenly appears. To return to the game, key
OK at the phony DOS prompt. Also known by some as the SpouseKey
D (Demo toggle)
This allows you to put MLShut into Demo Mode, in which the
computer plays for all players.
Defaults to "No", allowing human play.
Esc (Exit command)
Use this key to end MLCrux before the game is over.
F (Fast Mode toggle)
If you just want to play the game, and not look at some of the
"animation" (such as the "growing" score), turning the Fast Mode
on will do it.
Defaults to "No", showing all animation.
I (Program Info)
Displays information about the program and the author.
While selecting a Crux, pressing "H" will cause the
computer to show you a possible move, if any. It may not be
your best move, though (See PC OPPONENT below)!
N (Next Prompt toggle)
This allows you to get rid of the "Press return for so-and-so's
turn" message, which some folks find annoying.
Defaults to "Yes", allowing the message to show.
P (Pips Mode) ?????
Allows you to select between dice with pips (dots) on them, or
with numerals on them.
Defaults to "Yes", showing the dots.
R (Round Prompt toggle)
This allows you to get rid of the "Round" message, which some
folks find annoying.
Defaults to "Yes", allowing the message to show.
S (Sound Mode toggle)
This allows you to turn on and off the sounds produced by the
game, which some folks find annoying.
Defaults to "Yes", producing sound.
T (TopTen scores command)
Displays the highest ten scores achieved on your machine. (This
information is stored in the file MLCRUX.SCR. Clearing the top
ten may be done by displaying the top ten and pressing Alt-C.)
W (Win/Loss Statistics command)
Displays the statistics for all games played in the current
session (Since player names were entered). These are always
shown at the end of each game, but this command allows you to
display them during play.
COMMAND LINE PARAMETERS
In the section above, several options are referred to as "toggles".
This simply means that they can be in a "Yes" or "No" state.
(Note that the state of these toggles can be determined by looking
at the legend appearing at the bottom of your screen. If the
toggle description there begins with a capital letter, the toggle
is in a "Yes" state. For example, if a legend reads "Sound fast",
the sound toggle is set to "yes", and the fast toggle is set to
Each of them has a "default", which is the state (either yes or no)
in which they start out when Crux begins.
I set the defaults to the way I felt was best, but you may think
If you find yourself always changing one or more of the toggles
each time you play, you might want to set them on the DOS command
Any toggle can be flipped to the opposite of its default (Fast Mode
= "Yes", for example) by keying the toggle's letter following the
program name (MLCRUX) when you start up the game.
So, if you wanted to set "Round Prompt" to No, and Fast Mode to
"Yes" (the opposites of their defaults), at DOS you would key:
"MLCRUX R F"
...without the quotes, followed by the Return key. Be careful that
you leave a space between MLCRUX and the toggle(s), or DOS won't
recognize what you are trying to do.
This allows you to tailor the game a little to your taste, and if
you put this statement into a DOS batch file or menu processor, it
will save you from setting these toggles each time you start the
Toggles only valid from the command line:
B (Black And White mode) ??????
If you are running a composite monitor on a color graphics card,
and the colors in MLCrux are hard to discern, keying "MLCRUX B"
at the DOS prompt will make MLCrux run in Black And White Mode.
Note that, since Crux is a color-oriented game, the Black
and White mode makes it more difficult to play.
Defaults to "Yes" if Monochrome adapter detected, "No"
If you have your mouse driver installed, but do not want to use
the mouse during MLCrux, keying "MLCRUX M" at the DOS prompt
will cause MLCrux to ignore the mouse.
If you run the program without this parameter, you can still use
the keyboard. Using this parameter simply keeps the mouse
cursor from being displayed.
If the mouse driver is not installed, this parameter has no
Defaults to "Yes" if mouse driver detected, "No" otherwise.
T (Top Ten Scores)
This is different than the "T" command available during game
play. It specifies whether a Top Ten Scores file should be
saved, and is useful if you are running the game from a write-
Defaults to "Yes".
THE PC OPPONENT
The optional computerized opponent will play if you answer "Yes"
to the question "Play against the PC?".
The PC opponent's strategy isn't a very good one.
It merely looks at all of the pieces in its hand, and tries them
in every open space in the board, in all four rotations. It
then plays the piece which gives it the highest score. It does
NOT try to play a piece in such a way as to maximize its next
This is the same strategy the computer uses when you select a
hint, by the way.
In future versions of the game, I might make the PC opponent
smarter, so beat it now, while you can!
DIFFERENCE BETWEEN VERSIONS
VERSION 0.1 - 01/01/91
Not even a beta version, played only by author.
VERSION 0.2 - 07/07/91,
VERSION 0.4 - 12/06/91
Still incomplete, released to pre-beta tester.
Still incomplete, released to brave pre-beta tester.
VERSION 1.0 - 12/16/91
SHARING THE GAME WITH OTHERS
Crux is shareware. You can freely give copies of it to others,
provided that both files (MLCRUX.EXE and MLCRUX.DOC) are included,
Most Shareware requires a donation for continued use. Crux is a
little different in that registrations/donations are encouraged and
appreciated, but not required (see "Feedback" below).
You are also encouraged to upload it to any bulletin boards which
allow the uploading of games. For consistency's sake, please
upload the file with the file name MLCRUX10.ZIP (or .ARC, etc).
This indicates the version number (1.0), and will distinguish it
from any future versions I may produce.
Thanks to Austin Mereno for being my beta guinea-pig.
Thanks to Ed Tittel and Bob LeVitus for including some of my
earlier games in their "Stupid PC Tricks" and "Phenomenal PC Games"
Thanks to all those folks who wrote nice letters and left great BBS
messages in response to my other games.
A tip o' the hat as always to the officers and members of MicroLink
PCUG for the encouragement and support they always give my PC
The Tom Swan, Ben Ezzell and Jeff Duntemann mentioned in the
dedication are writers reponsible for a large body of books and
articles on (among other things) Turbo Pascal. These gents have
been an enormous help to me and every other Turbo Pascal programmer
I know. Anyone interested in learning the language would do well
to check into their works.
Thanks to Eagle Performance Software, whose Shareware product
"QWIK" allows for some blazingly fast screenwrites in Turbo Pascal
and Turbo C.
Programmers interested in QWIK should contact Eagle at:
Eagle Performance Software Or Call Jim LeMay at:
TP products (817) 735-4833
P.O. Box 122237
Fort Worth, TX 76121-2237
ALSO BY THE AUTHOR
MicroLink Yaht - The popular dice game
MicroLink Shut The Box - The traditional board game
MicroLink Otra - A memory game in the spirit of "Simon"
MicroLink Loyd - The "15" puzzle, in competitive game form
MicroLink Push Your Luck - A simple, fast-paced dice game
I would appreciate any comments, complaints, or wish lists of
features you'd like to see! And, if you have any favorite old
games you'd like to see programmed, I'm always looking for another
which would interest me!
Also, if you like the game enough (and can afford) to send a small
($5) donation, I won't argue. And my wife will understand my long
nights at the PC a little better!
Either way: Enjoy the game, and give copies of it to all your
friends. And enemies. Strangers on the street...
I can be contacted by mail at:
Bob Lancaster / P.O. Box 5612 / Hacienda Heights, CA 91745
Or by modem at:
MicroLink PCUG BBS (AKA So. Cal Builder's Board)
818/961-7903 - 24hrs/365 days - 300/1200/2400/9600
Please include the version number of Crux in correspondence.
Those interested in finding out more about MicroLink can contact
the board listed above, or by mail:
MicroLink PCUG Headquarters
15865-B E. Gale Ave. Box 1003
Hacienda Heights, CA 91745
Tell them Crux sent you!