diff --git a/grid.py b/grid.py
index baa20c0..7ab23c8 100644
--- a/grid.py
+++ b/grid.py
@@ -9,7 +9,8 @@ ON = True
 
 
 class GridTransformation(Enum):
-    FLIP_HORIZONTALLY = 1
+    FLIP_X = 1
+    FLIP_HORIZONTALLY = 1  # alias for FLIP_X; prep for 3d-transformations
     FLIP_VERTICALLY = 2
     FLIP_DIAGONALLY = 3
     FLIP_DIAGONALLY_REV = 4
@@ -26,19 +27,18 @@ class Grid:
         self.minY = 0
         self.maxX = 0
         self.maxY = 0
+        self.minZ = 0
+        self.maxZ = 0
+        self.mode3D = False
 
     def __trackBoundaries(self, pos: Coordinate):
-        if pos.x < self.minX:
-            self.minX = pos.x
-
-        if pos.y < self.minY:
-            self.minY = pos.y
-
-        if pos.x > self.maxX:
-            self.maxX = pos.x
-
-        if pos.y > self.maxY:
-            self.maxY = pos.y
+        self.minX = min(self.minX, pos.x)
+        self.minY = min(self.minY, pos.y)
+        self.maxX = max(self.maxX, pos.x)
+        self.maxY = max(self.maxY, pos.y)
+        if self.mode3D:
+            self.minZ = min(self.minZ, pos.z)
+            self.maxZ = max(self.maxZ, pos.z)
 
     def toggle(self, pos: Coordinate):
         if pos in self.__grid:
@@ -48,6 +48,9 @@ class Grid:
             self.__grid[pos] = not self.__default
 
     def set(self, pos: Coordinate, value: Any = True):
+        if pos.z is not None:
+            self.mode3D = True
+
         if (value == self.__default or value in OFF_STATES) and pos in self.__grid:
             del self.__grid[pos]
         elif value != self.__default and value not in OFF_STATES:
@@ -66,28 +69,41 @@ class Grid:
         else:
             return self.__grid[pos] not in OFF_STATES
 
-    def getValue(self, pos: Coordinate) -> any:
-        if pos not in self.__grid:
-            return self.__default
-        else:
-            return self.__grid[pos]
-
     def getOnCount(self):
         return len(self.__grid)
 
     def isSet(self, pos: Coordinate) -> bool:
         return pos in self.__grid
 
+    def getCorners(self):
+        if not self.mode3D:
+            return [
+                Coordinate(self.minX, self.minY),
+                Coordinate(self.minX, self.maxY),
+                Coordinate(self.maxX, self.minY),
+                Coordinate(self.maxX, self.maxY),
+            ]
+        else:
+            return [
+                Coordinate(self.minX, self.minY, self.minZ),
+                Coordinate(self.minX, self.minY, self.maxZ),
+                Coordinate(self.minX, self.maxY, self.minZ),
+                Coordinate(self.minX, self.maxY, self.maxZ),
+                Coordinate(self.maxX, self.minY, self.minZ),
+                Coordinate(self.maxX, self.minY, self.maxZ),
+                Coordinate(self.maxX, self.maxY, self.minZ),
+                Coordinate(self.maxX, self.maxY, self.maxZ),
+            ]
+
     def isCorner(self, pos: Coordinate) -> bool:
-        return pos in [
-            Coordinate(self.minX, self.minY),
-            Coordinate(self.minX, self.maxY),
-            Coordinate(self.maxX, self.minY),
-            Coordinate(self.maxX, self.maxY),
-        ]
+        return pos in self.getCorners()
 
     def isWithinBoundaries(self, pos: Coordinate) -> bool:
-        return self.minX <= pos.x <= self.maxX and self.minY <= pos.y <= self.maxY
+        if self.mode3D:
+            return self.minX <= pos.x <= self.maxX and self.minY <= pos.y <= self.maxY \
+                   and self.minZ <= pos.z <= self.maxZ
+        else:
+            return self.minX <= pos.x <= self.maxX and self.minY <= pos.y <= self.maxY
 
     def add(self, pos: Coordinate, value: Union[float, int] = 1):
         self.set(pos, self.get(pos) + value)
@@ -112,7 +128,8 @@ class Grid:
         for neighbour in pos.getNeighbours(
                 includeDiagonal=includeDiagonal,
                 minX=self.minX, minY=self.minY,
-                maxX=self.maxX, maxY=self.maxY):
+                maxX=self.maxX, maxY=self.maxY,
+                minZ=self.minZ, maxZ=self.maxZ):
             if neighbour in self.__grid:
                 if includeNegative or self.__grid[neighbour] > 0:
                     neighbour_sum += self.__grid[neighbour]
@@ -125,6 +142,9 @@ class Grid:
         self.set(c2, buf)
 
     def transform(self, mode: GridTransformation):
+        if self.mode3D:
+            raise NotImplementedError()  # that will take some time and thought
+
         if mode == GridTransformation.FLIP_HORIZONTALLY:
             for x in range(self.minX, (self.maxX - self.minX) // 2 + 1):
                 for y in range(self.minY, self.maxY + 1):