Luckily, agent x0 and 0x came and saw the signs.  
They knew that, for normal kinematics,the magnitude of distances AB=BA, 
BC= CB, CD=DC...etc 
"So, the table is wrong, it should have 6 different pair of numbers." said x0. 
"But why? How?!" asked 0x. 
"easy. Just find the sign that has 3 correct distances!", said x0. 
 
Then... 
FOR(A=TRUE) 
D=0; 
IF(B=2) 
C=1 is FALSE. 
ELSE 
C=2 is FALSE. 
=>FALSE 
 
FOR(C=TRUE) 
all signs have atleast 1 correct distance. 
=>FALSE 
 
FOR(D=TRUE) 
No sign can have 2 correct distances. 
=>FALSE 
 
FOR(B=TRUE) 
=>TRUE 
(signB has 3 correct distances) 
And 
The Table is: 
 
X. 19 17 16 
19 X. 18 15 
17 18 X. 20 
16 15 20 X. 
 
...why, some crazy dudes mustve changed two '9's to '6' and one '15' to 20. 
 
 
O_x