Index: src/game.d
==================================================================
--- src/game.d
+++ src/game.d
@@ -238,25 +238,39 @@
 		return true;
 	}
 	
 	Tuple!(int,bool) command(char c, int turn)
 	{
+		assert( this[robot] == 'R' );
 		if(c=='R') return move( 0, +1, turn);
 		if(c=='L') return move( 0, -1, turn);
 		if(c=='U') return move(+1,  0, turn);
 		if(c=='D') return move(-1,  0, turn);
 		if(c=='W') return move( 0,  0, turn);
+		if(c=='S') return use_razor(turn);
 		assert(false);
 	}
+
+	Tuple!(int, bool) use_razor(int turn)
+	{
+		if(razor) {
+			razor--;
+			for(int dy=-1; dy<=+1; ++dy)
+			for(int dx=-1; dx<=+1; ++dx)
+				if(this[robot.y+dy,robot.x+dx] == 'W')
+					this[robot.y+dy,robot.x+dx] = ' ';
+		}
+
+		bool dead = update(turn);
+		return tuple(0,dead);
+	}
 
 	Tuple!(int, bool) move(int dy, int dx, int turn)
 	{
 		int y = robot.y;
 		int x = robot.x;
-		assert( this[robot] == 'R' );
 		int lambda = 0;
-		bool dead = false;
 		if( '\\' == this[y+dy,x+dx] )
 			lambda++;
 		if( '!' == this[y+dy,x+dx] )
 			razor++;
 		if( " \\!.O".count(this[y+dy,x+dx])==1 ) {
@@ -274,12 +288,11 @@
 			foreach(p; tr_source[this[tp]])
 				this[p] = ' ';
 			this[tp] = 'R';
 			robot = tp;
 		}
-		if( update(turn) )
-			dead = true;
+		bool dead = update(turn);
 		return tuple(lambda,dead);
 	}
 
 	bool update(int turn)
 	{

Index: src/gui.d
==================================================================
--- src/gui.d
+++ src/gui.d
@@ -141,13 +141,14 @@
 		case Keys.DOWN:  fn('D'); break;
 		case Keys.UP:    fn('U'); break;
 		case Keys.LEFT:  fn('L'); break;
 		case Keys.RIGHT: fn('R'); break;
 		case Keys.W:     fn('W'); break;
+		case Keys.S:     fn('S'); break;
 		case Keys.A:     fn('A'); break;
 		case Keys.G:     fn(solver.single_step()); break;
 		default:         break;
 		}
 	}
 
 	Solver solver;
 }