diff --git a/labyrinth.py b/labyrinth.py
index f658e667a7dd1b1d4bd6b8a2c3800b1bb4f7e861..7d7d3e2a1e7bc255364f98dccc766f0fcb4037b0 100644
--- a/labyrinth.py
+++ b/labyrinth.py
@@ -39,7 +39,7 @@ class Labyrinth:
 		if width is not None: # empty labyrinth of given size
 			assert height is not None
 			assert stream is None
-			self.tiles = [[Labyrinth.Field(GroundType.FLOOR,col,row,self) for col in range(width)] for row in range(height)]
+			self.tiles = [[Labyrinth.Field(Labyrinth.GroundType.FLOOR,col,row,self) for col in range(width)] for row in range(height)]
 		elif height is not None:
 			assert False # width None, height not
 		elif stream is not None:
@@ -51,10 +51,10 @@ class Labyrinth:
 		for rownum,line in enumerate(stream):
 			row = []
 			for colnum,char in enumerate(line):
-				if char in [' ','0']:
-					row.append(Labyrinth.Field(GroundType.FLOOR,colnum,rownum,self))
+				if char in [' ','0','_']:
+					row.append(Labyrinth.Field(Labyrinth.GroundType.FLOOR,colnum,rownum,self))
 				elif char in ['W','w','#','1']:
-					row.append(Labyrinth.Field(GroundType.WALL,colnum,rownum,self))
+					row.append(Labyrinth.Field(Labyrinth.GroundType.WALL,colnum,rownum,self))
 			tiles.append(row)
 		return tiles