FOLCKs – Frank’s OnLine ChecKers

How to use it

… plus some details

Offline usage

If you want to use FOLCKs offline, you do the following:


Currently the following hotkeys are supported:

FToggle Formation text box.
LSwitch setting for Line of sight.
MToggle Mark of dancer(s).
SChange setting for Snapping.
YToggle Symmetric choreography.
During a ‘Dance’
C,N, X,VShow colors, couple numbers and/or sex temporarily when switched off;
e. g. for practising mental image calling. On touchscreens, this is done
by touching the corresponding text next to the pull-down menu.
EActive dancer(s) face Left
RActive dancer(s) face Right
TActive dancer(s) do a U-Turn Back
AltWhen pressed while moving or turning the dancers:
Do not add the new formation to the undo history.

Using URL Parameters

Some of the settings that can be made in the menu (and some additional as well) can also be changed by means of URL parameters.

Using URL parameters can help you to start FOLCKs with your favorite settings without the necessity to change them on each start.

URL parameters can be added to both, online and offline URLs.

Currently the following parameters are supported:

SettingMeaningPossible values/ExplanationDefaultMenu
angRotation angle (for
-90..90, but not 0
Recommended: 7.5, 15, 22.5, 30, 45, 60, 90
The value is rounded down (cut off) to three decimal places;
Negative values will change the direction for the mousewheel,
but have no effect for turning the dancers by the nose.
Locking angle (for
turning by the nose)
Show colors,
numbers and/or
sex of dancers
all: show for all dancers
none: don't show any
any combination of B1..B6 and G1..G6:

Show on listed dancers.
If the combination is already in the menu, it will be selected;
if not, it will be added and selected.
If a setting is invalid, it will be considered as ‘none’.

losShow line
of sight
none: don't show
turn: show while turning
turnsym: same as above, but consider symmetry
active: show on active dancer
activesym: same as above, but consider symmetry
always: well, always
madMark active
0 = no
1 = yes
nocNumber of
1, 2, 4, 64
snapSnapping into
0: No snapping
1, 2, 4, 8, 16: Dancers snap to 1/nth of the grid.
symUse symmetric
0 = no
1 = yes
floorSize of floorAny even number 2 ≤ n ≤ 16
Will be interpreted as dancefloor size of n*n (2*2, 4*4, 6*6, …)

Make sure that floorminfloorfloormax and
floormin < floormax.
floorminMinimum area
for zooming
floormaxMaximum area
for zooming
showstateDisplay the
formation string
in a text box
See section 'Setting and sharing the formation'
startGive a certain
to go into
form empty


To set a parameter on the URL the following rules apply:

  1. For the first parameter, write a questionmark (?) behind the original URL ( followed by the name of the setting (e. g. noc), an equal sign (=) and the value you want to assign (e. g. 2).
  2. If you want to change another setting, write an ampersand (&) followed by the name of the setting (e. g. sym), an equal sign (=) and the value you want to assign (e. g. 0).
  3. You can add as many settings as you want following rule (2).
  4. The order of the settings is not important, as long as the first parameter is lead by a questionmark and all the following settings are lead by an ampersand.
  5. There must be no spaces or other characters between questionmark, ampersand, equal sign, name of the setting and the value.
  6. Whenever an invalid or empty parameter is given, the default is used.
  7. If you do not want to change a setting, you can use the default value OR omit the corresponding parameter completely.

Settings can still be changed in the menu if available.


You can create a shortcut/link – e. g. on your desktop or home screen – with your preferred settings and you can also create multiple shortcuts/links to start with different settings.

Setting and sharing formations


This sections explains how to set the (starting) formation of your square and how to share formations with other callers or dancers.

You can set the formation of your square in two different ways:

Althought the resulting formation will be the same, there is an important difference between these to possibilities.

The formation text box

To show the formation as text you have to enable the formation text box. This can be done by adding another URL parameter; pressing F on the keyboard toggles the box. The way the formation is displayed depends on the parameter used in the URL:

no – do not show the text box (default)
yes – all in one line, no line break (default when the box is turned on by F)
lines – one line per dancer – easier to read and to modify
table – easiest to read and to modify
url – show the formation as URL

To copy the text from the box, just select it and press Ctrl+C. To enter a formation into the box, paste it with Ctrl+V and hit the return key. Make sure that the previous formation is deleted or overwritten before pressing return. You can also edit the string in the text box and press enter to change the formation without touching the dancers.

By entering multiple formations successively, you can create a kind of animation.


Setting the Formation via URL

To use the parameters, the general rules as above apply. There are two URL parameters that can be used to set the formation: start and form:

Changing the Appearance

If you – for whatever reason – want to change the appearance of the dancers (or of the whole website), you can change almost everthing by means what is called ‘custom stylesheets’. Depending on the web browser you are using, you have several options. Unfortunately, this does not work on smartphones or tablets. :-(

First of all, you should download the example file userContent.css and open it in a text editor.

Now, the easiest way to apply this file is to use a browser plug-in, also called ‘add-on’. For the Windows programs Chrome, Edge, Firefox and Opera I recommend Live editor for CSS, Less & Sass - Magic CSS (For Apple computers, I cannot give a recommendation). There are much more plug-ins available, but this one works really well and it supports local files as well (if you want to use FOLCKs offline). You have to install the plug-in via the browser’s menu (which is of course different for each browser), restart the program (just to be sure …) and activate the plug-in, which opens a small windows. Copy the content of userContent.css into the small window. I suggest that you do this step by step so you can better see what the changes are.

Now you can change the existent settings or add some others according to your wishes or need. Once you’re satisfied whith the changes, you can close the small window. When you close the browser and restart it, you may have to re-activate the plug-in (browser-dependent), but the settings are persistent.

Some browsers (e. g. Firefox for Windows) allows you to use the file userContent.css directly whithout a plug-in. To do so, you have to know where the file is located in the browser’s profile folder and modify it. Since the location varies for each browser, I cannot tell you exactly where to look. But I do know that for Firefox it is in %USERPROFILE%\AppData\Roaming\Mozilla\Firefox\Profiles\<profilename>.default\chrome\ where <profilename> is a combination of eight letters and numbers.

Note: The example userContent.css is not meant to create a beautiful result, it is mere an example of what is possible. Besides that, some of the settings early in the file are useless due to some later settings. Example: First the color of the grid is changed, then the grid is removed completely. Other settings can only be used if they are accompanied by others (having the nose on the outside only requires that is is made completely round as well).

Version Information

Current Version:


History (Minor changes are not listed.)

  • New, more intense colors and new icons
  • New URL parameter showsex plus new hotkey X for toggling
  • Lock dancers to flagpole with new hotkey P
  • URL parameter for angle can now have three decimal places
  • Hotkeys for turning dancers changed:
      Works now also for active dancers when not moved
  • When setting the formation via textbox or URL, the number of
      couples and the symmetry are determined from the given formation.
  • Bug fixes
  • Show formation in text box also as URL
  • More options for colors and couple numbers
  • New URL Parameter showcol and shownum
  • Hotkeys to show colors and couple numbers temporarily
  • Hotkeys to turn dancers automatically
  • Colors of couples #5 & #6 changed
  • Bugfix for offline version
  • Show formation in text box also as URL
  • Set dancefloor size via URL parameter
  • Set limits for dancefloor zooming via URL parameter
  • Settings for line of sight and snapping as buttons
  • Change number of couples via URL parameter
  • Show formation string in a text box (new URL parameter)
  • Set formation via URL parameter
  • Show line of sight via URL parameter
  • Change snapping via URL parameter
  • Undo history added
  • URL parameters introduced
  • Dancefloor sligthly bigger
  • Zoom dancefloor via slider
  • Special treatment for touchscreens
  • First published


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