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The FCB Cypher

Page history last edited by dave@layhands.com 14 years, 2 months ago

The current version is:- 4.30


FCB Cypher Version 4.30  incorporates a KnotTyer3D parser, undo, active palette tile highlighting, and tile rotating.


Downloads      FCB.exe       --  User Guide               --  Paper Template    FCB4.pdf


The FCB Cypher was designed to be a means of communicating a knot structure using a string of text characters which can be sent via a simple email, forum post or even communicated by spoken word in an unambiguous manner.  Now, with the inclusion of teh knots 'Binary Signature' and 'Find' facility, the utility offers the oportunity to draw a knot and then go straight to its entry in 'The Knot Library'.


The structure of the cypher is credited to Frank Charles Brown.


The basis of the cypher is the use of a set of predefined image tiles of cord ends, elbows and crossings.  These tiles each have an identification  code.  Tiles are copied into a grid to create the knot diagram.  A 'cypher', or 'code string' is then built up from that diagram by writing down a string of terms, each term describes the image tile present in each of the used grid squares.


Version 4 uses a letter coded grid where aa denotes the top left hand corner and a template of 18 drawing 'tiles' coded a..r


The diagram is constructed using the 18 tiles and then the cypher is written using groups of three letters.  The cypher set 'abd' for example denotes the cell in the first column, second row and has the tile imade 'd' drawn in it.



in this picture, the 'working end' tile 'd' is drawn in square 'ab', then tile 'g' has been drawn in cell 'bb' etc.


The working set of tile images is identified by code letters in the following table.  A full definition of the symbols is here.





In Version 4.2 the structure of the cypher is defined as nine lines of text.  The following example is the cypher for the Reef Knot.


FCB Version 4.x

Reef Knot

ABoK #74, Square Knot ABoK #1204


 cai daj dbh acc bcg ccl dcf ddh aem beg del

 bbi cbg eba bdf cdi edp ceh bfk cfl





Line 1 is a version identifier used by the windows drawing programme which created the cypher from a drawing.

Line 2 is the name of the knot

Line 3 is additional information such as ABoK reference number, AKA, etc

Line 4 is the Overs Index of the knot

Line 5 is the cypher for the first cord

Line 6 is the cypher for the second cord

Line 7 is the cypher for the third cord

Lines 8 and 9 record the position of any displayed spars.



The cypher lines are sets of three characters denoting the cell and its tile, separated by a single space.

The cypher file sample above would have been created by this diagram:-



If the file is loaded back into FCB4.exe, then the programm will read the cypher and recreate the diagram.


Code Examples are given here -  FCB Cypher Examples with diagrams.


NOTE:  Cyphers created in versions prior to 4.2 will show an anololy in tiles 'c' and 'd' as these have been exchanged in version 4.2.


A windows program has been developed to create cyphers, and to draw diagrams from cypher files

the program can be downloaded from the link at the top of this page.


Version 1

Initial concept - pencil and paper version.


Version 2

Evolving revisions which were quickly superceeded by the windows program supported V3


Version 3

Movement to the three letter cypher and the development of the windows drafting and display program


Version 4

The present protocol and drawing version incorporating three cords each represented by its own cypher line and a number of manipulation tools, together with automatic Overs Index calculation and Binary Signature calculation.  The utility can then link directly to The Knot Library to display information recorded under that particular binary signature.


Version 5

Proposals for consideration for inclusion in V5 - when it begins.

Comments (4)

DerekSmith said

at 8:18 am on Mar 21, 2008

Thoughts for the next revision.

Add facility to have multiple cypher strings, one string of cypher codes for every cord in the knot.

Add facility to 'reverse the knot i.e. create the left handed / right handed version from the given knot.

Remove the Print function to help make the world greener.

DerekSmith said

at 1:50 pm on Mar 31, 2008

The Windows program FCB4.exe is being written in Turbo Delphi Pro. Anyone interested in contributing to the project, please get in touch with me.

DerekSmith said

at 5:40 pm on Apr 6, 2008

Latest version 4.1 has full resizing facility enabled.

DerekSmith said

at 9:06 am on Jul 14, 2008

Version 4.2 Issued 14 July 2008 has Overs Index compute, Binary Signature compute and a facility to search The Knot Library using the Binary Signature as a link.

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