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Beware that y is an alternative mode to m or c. So that yc would range-toggle on an empty square, but not when you make a capture. It is true that Advancer capture has to be specified as a 3-leg move, to exclude pure rifle capture to an adjacent square. But the proper way to do that is make the first leg the slider move to the final destination (which always should be empty), and from there make the rifle-capture step in the forward direction: yafmcabQ. This still suffers from the edge or a friendly piece blocking the move.

A possible extension of XBetza would be to allow use of o on non-final legs in the meaning of moving beyond the board edge. (Which basically is also what the original Betza o does on a final leg, except that it then maps the piece back to the board as if the latter were a cylinder.) By writing yafmcoabQ the problem of approaching an edge would then be solved, as the second leg could then go to an empty square, an enemy or off board. The only thing it could not do was approach a friendly piece.

If the second leg would also have a p mode it could hop over a friendly piece, solving the problem of blocking by such a piece. But alas, it could then also hop over an enemy piece, so that capture becomes optional. In the XBoard implementation of XBetza there is a t modifier, which in combination with p or g would mean friendly hopping only. But the Interactive Diagram does not implement that. But since the introduction of the u ('unload') modifier, there is an alternative: instead of a hop on the second leg you can specify a friendly capture d, and then on the next leg unload the captured piece: yafdabuQ. (This relies on a u leg unloading the piece that was captured last during the move, not necessarily the piece captured at the final destination.