+static game_state *solve_game(game_state *state, game_aux_info *aux,
+ char **error)
+{
+ game_state *ret = dup_game(state);
+ int i;
+
+ /*
+ * Simply replace the grid with a solved one. For this game,
+ * this isn't a useful operation for actually telling the user
+ * what they should have done, but it is useful for
+ * conveniently being able to get hold of a clean state from
+ * which to practise manoeuvres.
+ */
+ for (i = 0; i < ret->n; i++)
+ ret->tiles[i] = (i+1) % ret->n;
+ ret->gap_pos = ret->n-1;
+ ret->used_solve = ret->just_used_solve = TRUE;
+ ret->completed = ret->movecount = 1;
+
+ return ret;
+}
+
+static char *game_text_format(game_state *state)
+{
+ char *ret, *p, buf[80];
+ int x, y, col, maxlen;
+
+ /*
+ * First work out how many characters we need to display each
+ * number.
+ */
+ col = sprintf(buf, "%d", state->n-1);
+
+ /*
+ * Now we know the exact total size of the grid we're going to
+ * produce: it's got h rows, each containing w lots of col, w-1
+ * spaces and a trailing newline.
+ */
+ maxlen = state->h * state->w * (col+1);
+
+ ret = snewn(maxlen+1, char);
+ p = ret;
+
+ for (y = 0; y < state->h; y++) {
+ for (x = 0; x < state->w; x++) {
+ int v = state->tiles[state->w*y+x];
+ if (v == 0)
+ sprintf(buf, "%*s", col, "");
+ else
+ sprintf(buf, "%*d", col, v);
+ memcpy(p, buf, col);
+ p += col;
+ if (x+1 == state->w)
+ *p++ = '\n';
+ else
+ *p++ = ' ';
+ }
+ }
+
+ assert(p - ret == maxlen);
+ *p = '\0';
+ return ret;
+}
+
+static game_ui *new_ui(game_state *state)
+{
+ return NULL;
+}
+
+static void free_ui(game_ui *ui)
+{
+}
+
+static game_state *make_move(game_state *from, game_ui *ui,
+ int x, int y, int button)