First, sorry for the mistakes for the letters "t,h,d,l,w,6,7,T,O,H,L,W,K" : hexa code was false.
After further observations, the solution was the RAIL.

As showed, it seems that the constructors minimized the alternance of tooth and vertical line.
On the Rail, we find a code whose complement to one ( changing all 1 to 0 and all 0 to 1) give the pi matrix.
Here is a short BASIC programm ( in QB) that does the conversion.
DIM n AS INTEGER, i AS INTEGER, k AS INTEGER
DIM code AS STRING, c AS STRING, bit AS INTEGER
n = 1
CLS
WHILE n > 0
INPUT "Nø du canal;0 pour terminer "; n
IF n > 0 THEN
k = n + 2
code = ""
c = ""
FOR i = 1 TO 7 ' nø OF bit
bit = k AND 1
k = INT(k / 2)
c = c + STR$(bit)
code = code + STR$((bit + 1) AND 1)
NEXT i
CLS
PRINT "canal="; n, "Matrix="; c, "Rail="; code
END IF
WEND
END
Before putting this on the web, I would like a confirmation of my observations.