The Tweedledee bowline

[Ruby]

Oh, no need to ignore their similarity

they sure are not same, but there's remarkable similariry,
and so they're named tweedledee and tweedledum,
which means twins , hard to distinguish, by looking. 

the diff point is inside the knot knub, an additional crossing

[X1]

they sure are not same, but there's remarkable similariry, and so they're named tweedledee and tweedledum,
which means twins, hard to distinguish, by looking.

 
  Their claimed "similarity" is only skin deep. I will never call "similar" two knots of different topology ! Is the 0 similar to 1 ? Is the sphere "similar" to a torus / donut ? Especially in this case, the one bend can be turned into a PET eye-knot, while the other can not. Big, HUGE difference ! The "remarquable similarity" and the names chosen by R.E.Miles were unfortunate mistakes ! The Teweedledum ( M. B 24 ) is more "similar" to the "Flat square knot ( M. B 29 ).
   The road to call "similar" all the knots that it is hard to distinguish by looking ( but very easy by tying or untying...), is a very slippery one ! Imagine how many completely different knots, indeed, things, you will be forced to call "similar" !
   
   For a FINE, in depth exposition on the issue of the so-called "similarity" of various bends, see :
   http://charles.hamel.free.fr/knots-and-cordages/Investigation_6.html 

[Ruby]

Tweedledum bend is formed by retucking a what knot 1406(grief?)


B29 or abok 803 is formed by retucking a reef knot, very very very difficult to untie

[X1]

B29 is... very very very difficult to untie

  The "Oyster bend", which is just the Tweedledee bend with the "diagonal elements" on the outer mantle of the knot ( and can be tied with a corresponding tying method ) is much more difficult to untie ! In fact, it is the most tight / jamming knot I know ! So, you see, a "minor" detail can transform a prince into a frog, and vice versa. "Similarity" of knots is a notion that does more harm than good.