[Retros] Add units: 17th update

[Mu-Tsun Tsai]

> I decided against including Mu-Tsun's N12i (sorry Mu-Tsun), because

> i think we shall concentrate on problems with addition of 1 unit,

> then on problems maximizing the number of units to add (promoted

> pieces/non promoted pieces separated). So most of the lines between

> 2 and 17 units will be left blank.


That's OK. In that case, I would like to try proposing a 1KC problem.

Diagram:
http://www.janko.at/Retros/d.php?ff=8/pp6/7P/7P/p6P/p6P/p6P/R2k4
(6+6)

Stip: Add the missing unit(s).

Intended solution: +wKb1 (last move: bx?a2+)


See if this works!

Mu-Tsun