Unique solubility in Mines means that you can massively increase the

mine density without (as you would with a conventional random grid
generator) rendering the game completely unplayable. High mine
densities are really good fun, and the point of the presets menu is
to provide people with pre-tested good settings and things they
might not have thought to try for themselves; so here are three
additional presets with high densities.

[originally from svn r5906]

mines.c

@@ -97,8 +97,11 @@ static game_params *default_params(void)
 
 static const struct game_params mines_presets[] = {
   {9, 9, 10, TRUE},
+  {9, 9, 35, TRUE},
   {16, 16, 40, TRUE},
+  {16, 16, 99, TRUE},
   {30, 16, 99, TRUE},
+  {30, 16, 170, TRUE},
 };
 
 static int game_fetch_preset(int i, char **name, game_params **params)