New puzzle! Setting what might be a record for how long we've sat on

a puzzle before it was ready to commit, here is 'Signpost': a clone
of janko.at's "Arrow Path", by James Harvey.

[originally from svn r8861]

puzzles.but

@@ -2774,6 +2774,86 @@ row/column counts.
 time, making the puzzle more difficult.
 
 
+\C{signpost} \i{Signpost}
+
+\cfg{winhelp-topic}{games.signpost}
+
+You have a grid of squares; each square (except the last one)
+contains an arrow, and some squares also contain numbers. Your job
+is to connect the squares to form a continuous list of numbers
+starting at 1 and linked in the direction of the arrows \dash so the
+arrow inside the square with the number 1 will point to the square
+containing the number 2, which will point to the square containing
+the number 3, etc. Each square can be any distance away from the
+previous one, as long as it is somewhere in the direction of the
+arrow.
+
+By convention the first and last numbers are shown; one or more
+interim numbers may also appear at the beginning. 
+
+Credit for this puzzle goes to \i{Janko} \k{janko-arrowpath}, who call it
+\q{Pfeilpfad} (\q{arrow path}).
+
+Signpost was contributed to this collection by James Harvey.
+
+\B{janko-arrowpath}
+\W{http://janko.at/Raetsel/Pfeilpfad/index.htm}\cw{http://janko.at/Raetsel/Pfeilpfad/index.htm}
+
+\H{signpost-controls} \I{controls, for Signpost}Signpost controls
+
+To play Signpost, you connect squares together by dragging from one
+square to another, indicating that they are adjacent in the
+sequence. Drag with the left button from a square to its successor,
+or with the right button from a square to its predecessor.
+
+If you connect together two squares in this way and one of them has
+a number in it, the appropriate number will appear in the other
+square. If you connect two non-numbered squares, they will be
+assigned temporary algebraic labels: on the first occasion, they
+will be labelled \cq{a} and \cq{a+1}, and then \cq{b} and \cq{b+1},
+and so on. Connecting more squares on to the ends of such a chain
+will cause them all to be labelled with the same letter.
+
+When you left-click or right-click in a square, the legal squares to
+connect it to will be shown.
+
+The arrow in each square starts off black, and goes grey once you
+connect the square to its successor. Also, each square which needs a
+predecessor has a small dot in the bottom left corner, which
+vanishes once you link a square to it. So your aim is always to
+connect a square with a black arrow to a square with a dot.
+
+To remove any links for a particular square (both incoming and
+outgoing), left-drag it off the grid. To remove a whole chain,
+right-drag any square in the chain off the grid.
+
+You can also use the cursor keys to move around the grid squares and
+lines. Pressing the return key when over a square starts a link
+operation, and pressing the return key again over a square will
+finish the link, if allowable. Pressing the space bar over a square
+will show the other squares pointing to it, and allow you to form a
+backward link, and pressing the space bar again cancels this.
+
+(All the actions described in \k{common-actions} are also available.)
+
+\H{signpost-parameters} \I{parameters, for Signpost}Signpost parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares. There will be half \e{Width} \by \e{Height}
+dominoes in the grid: if this number is odd then one square will be blank.
+
+(Grids with at least one odd dimension tend to be easier to solve.)
+
+\dt \e{Force start/end to corners}
+
+\dd If true, the start and end squares are always placed in opposite corners
+(the start at the top left, and the end at the bottom right). If false the start
+and end squares are placed randomly (although always both shown). 
+
 
 \A{licence} \I{MIT licence}\ii{Licence}