xletters - catch falling words
is a game under X to improve your typing skill. It is inspired
by the game letters
(6) by Larry Moss and Brent Nordquist (which itself
is inspired by the game Letter Invaders
, and ultimately by the famous
The goal of the game is to destroy the words that fall down from the top before
they reach the bottom. To destroy a word, you must simply type it.
The game is organized in levels of increasing difficulty. Each level is divided
into two parts: a normal part and a bonus part. During the normal part,
ordinary english words will fall down (found in the system's dictionary,
). During the bonus part, the words are randomly
generated from printable ascii characters.
If a word hits the ground during the normal part, you lose a life (you have five
lives initially), and the word disappears (but the others keep on falling). If
a word hits the ground during the bonus part, the bonus part simply ends, with
no additional penalty, and the game proceeds to the next level.
The normal part of a level ends when a certain time has elapsed. The bonus part
ends when either a certain time has elapsed or when a word has hit the ground.
The normal duration of a half-level is 600 time units, or 45 seconds (whatever
Typing a word correctly makes the word disappear and scores you one point per
letter, plus five more points, plus another extra three points if the word was
destroyed in the top fifth of the window. This is the only way of gaining
points: partially typed words are not worth anything, and even moving to
another level doesn't bring you points (this is because even if you don't type
you will go beyond the first level).
Short words fall faster than long ones. Unless otherwise specified at compile
time, words are not allowed to collide into one another. Therefore, when a new
word appears, the game makes sure that all the words below it fall at least as
fast as it. The fall rate of the words also increases with the level (it is,
however, the same between the normal part and the bonus part of the same
level). The rate at which words appear is constant on a given level, but it
increases with the level.
A word is considered typed when the last printable characters that you typed
since the word appeared are precisely the letters of the word. This means in
particular that it is possible to ``kill two birds with one stone'' if one
word ends with the letters with which another one begins - in fact, if two
identical words appear (an unlikely but not impossible situation), you need
only type one of them. To say things differently, if you type a correct letter
it will make your position in the word advance by one letter, and if you type
an incorrect letter, it will make your position move back to the last place in
the word that matches the characters you typed. The current position in each
word is indicated by putting the already typed letters in a different color
(normally red). Note that a different behaviour is selectable at compile time
with which a wrong letter will cause all letters to be considered wrong (to
make the difference obvious, consider the word ``abracadabrx'': if after
having typed ``abracadabr'' you press an ``a'', the normal behaviour will take
you back to ``abra'' whereas the alternate behaviour will take you back to the
The game keeps a high score table. When the game is over, one way or another,
xletters will show, for the user and for the twenty best players, the name,
the level reached, the final score, and the time during which the game was
running. Normally, each player is allowed only one entry in the high score
table. This can be modified at compilation time, however.
The top of the window shows three buttons. The Quit
button will take you
out of the game, the Pause
button will pause the game or resume it if
it was already paused, and the Next
button will move to the next level
(normal part). These buttons can also be accessed through accelerators: the
``Escape'' key will quit the game, the ``Tab'' key (or ``Pause'' if you have
one) will suspend it or resume it, and the ``Page Down'' key (or ``Next'' if
it is so labeled) will advance one level.
Three labels on the right of the buttons are used to indicate your lives, score
and current level.
Other than that, to play the game you must simply type the words. In order for
the typing to be effective, your mouse cursor must be in the game space (the
large square area below the buttons and labels). If you start typing while the
game is paused, it will automatically resume.
Scoring is made much
more complicated if you choose to use the
button to warp through levels. (The point is that it should be
used to avoid having to go through all the easy levels if you already type
very fast. So it should not handicap you excessively by giving you no points
which you would have gotten if you had worked your way through those levels.
On the other hand, it should not be an obvious way of gaining arbitrarily many
points.) Here is the way it works: when you use the Next
button to warp
to the next level, you gain 350 ``virtual'' points. Those points are indicated
in parentheses after your real points in the score label. They are not worth
anything by themselves. On the other hand, if you have virtual points, every
time you gain some points, that many virtual points will also be converted to
real points (until you no longer have virtual points). Thus, virtual points
are worth something only if you prove yourself good enough to make them so.
There are some restrictions to the use of the Next
button. First, it will
only work in the bonus part of a level, or if no word has fallen lower than
the top fifth of the screen. This is so you can't use it to get yourself
easily out of a tricky situation. Second, if you already scored some points on
the current level, using the Next
button will award you fewer than the
normal 350 virtual points (see above), in fact precisely twice fewer than as
many points as you gained on the level (but no less than zero, of course).
has a training mode, which you can invoke using the
command line option. In training mode, only one (english) word
appears at a time, anywhere on the game space, and it does not fall. A new
word appears as soon as you finish typing the previous one. In training mode,
there are no lives, points, levels, or bonus words.
also has the amazing ``deathmatch'' mode. To invoke this mode,
use the -death
command line option. This has the following effects on
the behaviour of xletters
: first, it will read words on the standard
input, and make them fall. Second, you can choose between typing falling
words, or typing a special word in a special part of the display, just above
the game space. To switch between both modes, use the Mode
press the ``Backspace'' key. The special word typed must be an english word:
if the letter you type makes the word fragment no longer begin a word in the
dictionary, it immediately disappears. When you type a full word, you can then
send it by using the Send
button or by pressing the ``Return'' key. The
word sent gets printed on the standard output.
These features make sense when two
copies of xletters
are run in
deathmatch mode, with the standard output of each being sent to the standard
input of the other (possibly across the network). Then the player on each game
can not only kill his falling words but also send words to the other player.
Even more extreme than the ``deathmatch'' mode is the ``duel'' mode, activated
through the -duel
command switch. In duel mode, the computer does not
send words of its own, and only words sent through the standard input will
appear. In this case, there is no Next
button, and switching to the
next level can only occur after a certain amount of time. In fact, there are
no bonus parts of levels, so levels change twice more rapidly than in normal
play. Moreover, a level change does not erase all the current words contrary
to what happens in normal (or deathmatch) mode.
The X Letters
distribution includes a shell script named
which uses Avian Research's netcat
program (nc) to
open a socket, run xletters
in duel mode, and try to connect to the
same socket on a given computer. Thus, two people on two different computers
can play a duel by each running xletters-duel
with the name of the
other's computer as parameter. (Both copies must be run within five seconds of
recognizes all the standard X Toolkit command line options,
among which the following:
- -bg color
- Specifies the background color to use.
- -fg color
- Specifies the foreground color to use for the labels and
- -fn font
- Specifies the font to use for displaying the labels and
- -name name
- Specifies the application name under which resources are to
be obtained, rather than under the default executable file name.
name should not contain ``.'' or ``*'' characters.
- -title string
- Specifies the window title string.
- -geometry geometry
- Specifies the preferred position of the window. Specifying
a size is not recommended.
- -display display
- Specifies the X server to use.
- -xrm resourcestring
- Explicitely give a resource string.
The following additional options are recognized by xletters
- -wfn font
- Specifies the font to use for the falling words. (Sets the
- -wc color
- Specifies which color to use for the words. (Sets the
- -tc color
- Specifies which color to use for the correctly typed part
of the words. (Sets the typedColor resource.)
- -gbg color
- Specifies which color to use for the background of the game
space. (Sets the gameSpace.background resource.)
- Do not go in training mode (this is the default). (Sets the
trainingMode resource to ``False''.)
- Run the game in training mode (see TRAINING MODE
above). (Sets the trainingMode resource to ``True''.)
- Do not run in deathmatch or duel mode (this is the
default). (Sets the deathMode resource to ``normal''.)
- Run in deathmatch mode (see DEATHMATCH AND DUEL
above). (Sets the deathMode resource to ``death''.)
- Run in duel mode (see DEATHMATCH AND DUEL above).
(Sets the deathMode resource to ``duel''.)
In addition, xletters
- groundBox (class Box, parent (toplevel))
- This is the main application box that supports all the
- label (class Label, parent groundBox)
- The xletters label. The text of this label cannot be
- quitButton (class Command, parent groundBox)
- The Quit button.
- pauseButton (class Toggle, parent groundBox)
- The Pause button.
- livesLabel (class Label, parent groundBox)
- The lives label.
- scoreLabel (class Label, parent groundBox)
- The score label.
- levelLabel (class Label, parent groundBox)
- The level label.
- gameSpace (class Core, parent groundBox)
- The game space in which the words fall. Key presses and
Expose events are handled through event handlers and not the ordinary
In addition to the resources of the various widgets, the xletters
application itself recognizes some resources. These are:
- wordFont (class Font, type FontStruct)
- The font in which the falling words are written.
- wordColor (class Foreground, type Pixel)
- The color in which the (untyped part of the) falling words
- typedColor (class HighlightColor, type Pixel)
- The color in which the typed part of the falling words are
- deathMode (class DeathMode, type String)
- Either normal, death or duel according
as the game should be run in normal, deathmatch or duel mode (see
DEATHMATCH AND DUEL above).
- trainingMode (class TrainingMode, type Boolean)
- Whether the game should be run in training mode (this
overrides any value of the deathMode resource (see TRAINING
(If not overriden at compile time)
- The dictionary of words.
- The high score table.
xletters -wfn '-bitstream-terminal-medium-r-normal--18-*-*-*-c-*-iso8859-1' -gbg
'MidnightBlue' -wc 'PaleGoldenrod' -tc 'Orchid'
None known. Surely a very temporary situation :-)
This is one of the ugliest programs I ever wrote. I would not be surprized to
discover plenty of bugs in it. Version 1.0.0 was ugly enough. Version 1.1.0
gave a whole new meaning to the word ``uglyfication''.
wants to access a high score table. If this score table is to be
shared between several users, xletters
will probably be made sgid games
or some such thing. Beware that it is probably very easy to fool (or even
brake to pieces). I have no doubt that running it against a fake X server (and
probably other similar things) can give not-too-hard access to whatever
permissions it has been given. Consequently, it should not be given any
Peter Horvai (email@example.com) wrote the deathmatch feature and implemented
mmap()ing the dictionary file.
David Madore (firstname.lastname@example.org) wrote version 1.0.0, all the X Windows parts
of the game, and this man page.
GNU public license. See the file COPYING
for more information.