What does F2 mean? - Which nalbinding stitch is which?

Nalbinding stitches which I most often see people using in their items seem to be either Oslo Stitch or Mammen Stitch, but there are many others, too, and sometimes it can be confusing to try to remember all the names, or the logic of how one stitch changes to another.

So, how can you tell which nalbinding stitch is which?
Also connection stitches (F1, F2, B1...) are explained further below. 

York Stitch gets sometimes confused with Oslo Stitch. They both have 1 loop around thumb, and 1 loop behind thumb. In Oslo Stitch you insert the needle into the loop behind your thumb from front to back, while in York Stitch you insert the needle from back to front.

Oslo Stitch, on the other hand, gets sometimes confused also with Mammen Stitch. They both have 1 loop around thumb, but in Oslo Stitch you pick up 1 loop behind the thumb, while in Mammen Stitch you pick up 2 loops behind the thumb.

If you have a look at the numbers below each photo, you will see the first number indicates the number of thumb loops, and the second one tells how many loops are picked up behind the thumb. So in Oslo Stitch the number is 1+1, and in Mammen Stitch 1+2.

The numbers also match with the Us and Os (Hansen's Notation). So, Oslo Stitch is 1+1 or UO/..., and Mammen Stitch is 1+2 or UOO/...

• Edit: In case you have heard about Korgen Stitch, so basically Korgen Stitch and Mammen Stitch are the same (1+2 or UOO/UUOO) but in Korgen Stitch the connection stitch is F1 and in Mammen Stitch F2. See further below for F1s and F2s. 

Now, if you look at the next photos after Oslo Stitch and Mammen Stitch, I hope you get the logic how the stitches can be changed/varied.
Brodén Stitch - 1 thumb loop, 3 loops behind the thumb (1+3, UOOO/...).
Långaryd Stitch - 1 thumb loop, 4 loops behind the thumb (1+4, UOOOO/...).
Bålsta Stitch - 1 thumb loop, 5 loops behind the thumb (1+5, UOOOOO/...)

The Finnish Stitch variant I have chosen here involves 2 loops around thumb and 2 loops behind the thumb (ie. 2+2, or UUOO/...). If you think it, it is almost like Mammen Stitch except that there are 2 thumb loops. There are also stitch variants which involve 2 thumb loops and 3 to 5 loops behind the thumb (ie. 2+3 or 2+4 or 2+5).

Dalby Stitch is a bit different. There is 1 loop around thumb, 1 loop behind thumb is picked up from front to back (as usual), but the second loop behind the thumb is picked up from back to front (needle tip pointing to 9 o'clock *). So that would make 1+1+1 or UOU/...

• *) The direction matters, because if the needle tip points to the opposite direction, the stitch is one of the Turning Stitches, and the surface looks quite different, too. Turning Stitches are not included in these photos. 

Edit: These stitches shown here, obviously, are not the only one. 

The shortenings for connection stitches often seem to be a source of confusion.
F = front, B = back, M = middle

• Edit: These are not the only ways to connect new stitches to the previous row. For example Åsle Stitch connection is not show here, and it is also possible to pick up the connection stitch from the reverse side of the fabric, like in e.g. Vad Stitch. 

F1 = 1 loop at the upper/top edge, from front to back
F2 = 2 loops at the upper/top edge, from front to back - "1 new loop, 1 old loop"

B1 = 1 loop at the upper/top edge, from back to front
B2 = 2 loops at the upper/top edge, from front to back - "1 new loop, 1 old loop"

M - pay attention to the direction of the needle (either <-- or -->), because that changes the way the stitch surface will look like

M1+F1 = 1 loop at the mid row, 1 loop at the upper/top edge

F1B1 = 1 loop (new) from front to back, 1 loop (old) from back to front

Left bottom corner, the blue sample, shows the F2 connection ("under x") when your stitch has the so called plaited edge (see below).

On the left - "normal/usual" way of finishing the stitch
On the right - "plaited edge"