diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7e8ad3318..ccb8f5ff4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,7 +25,7 @@ set(DF_VERSION_MINOR "31")
 set(DF_VERSION_PATCH "25")
 set(DF_VERSION "${DF_VERSION_MAJOR}.${DF_VERSION_MINOR}.${DF_VERSION_PATCH}")
 
-set(DFHACK_RELEASE "3")
+set(DFHACK_RELEASE "4")
 
 ## where to install things (after the build is done, classic 'make install' or package structure)
 # the dfhack libraries will be installed here:
diff --git a/library/Core.cpp b/library/Core.cpp
index 6ca57703b..d7601d8b8 100644
--- a/library/Core.cpp
+++ b/library/Core.cpp
@@ -397,6 +397,8 @@ bool Core::Init()
 {
     if(started)
         return true;
+    if(errorstate)
+        return false;
 
     // find out what we are...
     #ifdef LINUX_BUILD
diff --git a/plugins/vdig.cpp b/plugins/vdig.cpp
index 9f3166d44..756646a2d 100644
--- a/plugins/vdig.cpp
+++ b/plugins/vdig.cpp
@@ -16,17 +16,21 @@ using std::stack;
 using namespace DFHack;
 
 DFhackCExport command_result vdig (Core * c, vector <string> & parameters);
+DFhackCExport command_result vdigx (Core * c, vector <string> & parameters);
 DFhackCExport command_result autodig (Core * c, vector <string> & parameters);
+DFhackCExport command_result expdig (Core * c, vector <string> & parameters);
 
 DFhackCExport const char * plugin_name ( void )
 {
-    return "vein digger";
+    return "vdig";
 }
 
 DFhackCExport command_result plugin_init ( Core * c, std::vector <PluginCommand> &commands)
 {
     commands.clear();
-    commands.push_back(PluginCommand("vdig","Dig a whole vein. With 'x' option, dig stairs between z-levels.",vdig));
+    commands.push_back(PluginCommand("vdig","Dig a whole vein.",vdig));
+    commands.push_back(PluginCommand("vdigx","Dig a whole vein, follow vein through z-levels with stairs.",vdigx));
+    commands.push_back(PluginCommand("expdig","Select or designate an exploratory pattern. Use 'expdig ?' for help.",expdig));
     //commands.push_back(PluginCommand("autodig","Mark a tile for continuous digging.",autodig));
     return CR_OK;
 }
@@ -35,6 +39,364 @@ DFhackCExport command_result plugin_shutdown ( Core * c )
 {
     return CR_OK;
 }
+typedef char digmask[16][16];
+
+static digmask diag5[5] =
+{
+    {
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+    },
+    {
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+    },
+    {
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+    },
+    {
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+    },
+    {
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+        {0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0},
+        {0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0},
+        {0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0},
+        {1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1},
+        {0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0},
+    },
+};
+
+static digmask ladder[3] =
+{
+    {
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0},
+        {1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1},
+        {0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0},
+        {1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1},
+        {0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0},
+        {1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1},
+        {0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0},
+        {1,0,1,1,0,1,1,0,1,1,0,1,1,0,1,1},
+        {0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0},
+    },
+    {
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0},
+        {0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0},
+        {0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0},
+        {0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0},
+        {0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0},
+        {0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0},
+        {0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0},
+        {0,1,1,0,1,1,0,1,1,0,1,1,0,1,1,0},
+        {0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1},
+    },
+    {
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0},
+        {1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1},
+        {0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0},
+        {1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1},
+        {0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0},
+        {1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1},
+        {0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0},
+        {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+        {0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0},
+        {1,1,0,1,1,0,1,1,0,1,1,0,1,1,0,1},
+        {0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0},
+    },
+};
+
+static digmask all_tiles =
+{
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+    {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
+};
+enum explo_how
+{
+    EXPLO_NOTHING,
+    EXPLO_DIAG5,
+    EXPLO_LADDER,
+    EXPLO_CLEAR,
+};
+
+enum explo_what
+{
+    EXPLO_ALL,
+    EXPLO_HIDDEN,
+    EXPLO_DESIGNATED,
+};
+
+DFhackCExport command_result expdig (Core * c, vector <string> & parameters)
+{
+    bool force_help = false;
+    static explo_how how = EXPLO_NOTHING;
+    static explo_what what = EXPLO_HIDDEN;
+    for(int i = 0; i < parameters.size();i++)
+    {
+        if(parameters[i] == "help" || parameters[i] == "?")
+        {
+            force_help = true;
+        }
+        else if(parameters[i] == "all")
+        {
+            what = EXPLO_ALL;
+        }
+        else if(parameters[i] == "hidden")
+        {
+            what = EXPLO_HIDDEN;
+        }
+        else if(parameters[i] == "designated")
+        {
+            what = EXPLO_DESIGNATED;
+        }
+        else if(parameters[i] == "diag5")
+        {
+            how = EXPLO_DIAG5;
+        }
+        else if(parameters[i] == "clear")
+        {
+            how = EXPLO_CLEAR;
+        }
+        else if(parameters[i] == "ladder")
+        {
+            how = EXPLO_LADDER;
+        }
+    }
+    if(force_help || how == EXPLO_NOTHING)
+    {
+        c->con.print("This command can be used for exploratory mining.\n"
+                     "http://df.magmawiki.com/index.php/DF2010:Exploratory_mining\n"
+                     "\n"
+                     "There are two variables that can be set: pattern and filter.\n"
+                     "Patterns:\n"
+                     "  diag5 = diagonals separated by 5 tiles\n"
+                     " ladder = A 'ladder' pattern\n"
+                     "  clear = Just remove all dig designations\n"
+                     "Filters:\n"
+                     " all        = designate whole z-level\n"
+                     " hidden     = designate only hidden tiles of z-level (default)\n"
+                     " designated = Take current designation and apply pattern to it.\n"
+                     "\n"
+                     "After you have a pattern set, you can use 'expdig' to apply it:\n"
+                     "'expdig diag5 hidden' = set filter to hidden, pattern to diag5.\n"
+                     "'expdig' = apply the pattern with filter.\n"
+        );
+        return CR_OK;
+    }
+    c->Suspend();
+    Gui * gui = c->getGui();
+    Maps * maps = c->getMaps();
+    uint32_t x_max, y_max, z_max;
+    if(!maps->Start())
+    {
+        c->Resume();
+        c->con.printerr("Can't init the map...\n");
+        return CR_FAILURE;
+    }
+    maps->getSize(x_max,y_max,z_max);
+    int32_t xzzz,yzzz,z_level;
+    if(!gui->getViewCoords(xzzz,yzzz,z_level))
+    {
+        c->Resume();
+        c->con.printerr("Can't get view coords...\n");
+        return CR_FAILURE;
+    }
+    auto apply = [&](uint32_t bx, uint32_t by, digmask & dm) -> bool
+    {
+        df_block * bl = maps->getBlock(bx,by,z_level);
+        if(!bl)
+            return false;
+        int x = 0,mx = 16;
+        if(bx == 0)
+            x = 1;
+        if(bx == x_max - 1)
+            mx = 15;
+        for(; x < mx; x++)
+        {
+            int y = 0,my = 16;
+            if(by == 0)
+                y = 1;
+            if(by == y_max - 1)
+                my = 15;
+            for(; y < my; y++)
+            {
+                naked_designation & des = bl->designation[x][y].bits;
+                short unsigned int tt = bl->tiletype[x][y];
+                // could be potentially used to locate hidden constructions?
+                if(tileMaterial(tt) == CONSTRUCTED && !des.hidden)
+                    continue;
+                if(!isWallTerrain(tt) && !des.hidden)
+                    continue;
+                if(how == EXPLO_CLEAR)
+                {
+                    des.dig = designation_no;
+                    continue;
+                }
+                if(dm[y][x])
+                {
+                    if(what == EXPLO_ALL
+                        || des.dig == designation_default && what == EXPLO_DESIGNATED
+                        || des.hidden && what == EXPLO_HIDDEN)
+                    {
+                        des.dig = designation_default;
+                    }
+                }
+                else if(what == EXPLO_DESIGNATED)
+                {
+                    des.dig = designation_no;
+                }
+            }
+        }
+        bl->flags.set(BLOCK_DESIGNATED);
+        return true;
+    };
+    if(how == EXPLO_DIAG5)
+    {
+        int which;
+        for(uint32_t x = 0; x < x_max; x++)
+        {
+            for(int32_t y = 0 ; y < y_max; y++)
+            {
+                which = (4*x + y) % 5;
+                apply(x,y_max - 1 - y,diag5[which]);
+            }
+        }
+    }
+    else if(how == EXPLO_LADDER)
+    {
+        int which;
+        for(uint32_t x = 0; x < x_max; x++)
+        {
+            which = x % 3;
+            for(int32_t y = 0 ; y < y_max; y++)
+            {
+                apply(x,y,ladder[which]);
+            }
+        }
+    }
+    else for(uint32_t x = 0; x < x_max; x++)
+        for(int32_t y = 0 ; y < y_max; y++)
+            apply(x,y,all_tiles);
+    c->Resume();
+    return CR_OK;
+}
+DFhackCExport command_result vdigx (Core * c, vector <string> & parameters)
+{
+    for(int i = 0; i < parameters.size();i++)
+    {
+        if(parameters[i] == "help" || parameters[i] == "?")
+        {
+            c->con.print("Designates a whole vein under the cursor for digging.\n"
+            "Also follows the vein between z-levels with stairs, like 'vdig x' would.\n"
+            );
+            return CR_OK;
+        }
+    }
+    vector <string> lol;
+    lol.push_back("x");
+    return vdig(c,lol);
+}
 
 DFhackCExport command_result vdig (Core * c, vector <string> & parameters)
 {