diff --git a/21g30t1e75.js b/21g30t1e75.js
index d381b9e..5efc7f2 100644
--- a/21g30t1e75.js
+++ b/21g30t1e75.js
@@ -220,22 +220,49 @@ GameLib.CustomCode.SnakeBody.prototype.applyToMesh = function() {
 
 GameLib.CustomCode.SnakeBody.prototype.advance = function(orientation, flip) {
 
-    if (orientation === GameLib.CustomCode.ORIENTATION_UP) {
-        this.position.y += 1;
-    }
-
-    if (orientation === GameLib.CustomCode.ORIENTATION_DOWN) {
-        this.position.y -= 1;
-    }
-
-    if (orientation === GameLib.CustomCode.ORIENTATION_LEFT) {
-        this.position.x -= 1;
-    }
-
-    if (orientation === GameLib.CustomCode.ORIENTATION_RIGHT) {
-        this.position.x += 1;
-    }
-
+	var crash = false;
+	
+	switch (orientation) {
+		case GameLib.CustomCode.ORIENTATION_UP : 
+			if ((this.position.y + 1) > GameLib.CustomCode.GRID_HEIGHT) {
+				crash = true;
+			} else {
+				this.position.y += 1;
+			}
+			break;
+		case GameLib.CustomCode.ORIENTATION_DOWN : 
+			if ((this.position.y - 1) < 0) {
+				crash = true;
+			} else {
+				this.position.y -= 1;
+			}
+			break;
+		case GameLib.CustomCode.ORIENTATION_LEFT : 
+			if ((this.position.x - 1) < 0) {
+				crash = true;
+			} else {
+				this.position.x -= 1;
+			}
+			break;
+		case GameLib.CustomCode.ORIENTATION_RIGHT : 
+			if ((this.position.x + 1) > GameLib.CustomCode.GRID_WIDTH) {
+				crash = true;
+			} else {
+				this.position.x += 1;
+			}
+			break;
+		default :
+			console.warn('unknown orientation');
+			break;
+	}
+	
+	if (!crash) {
+		console.log('check against body');
+	} else {
+		console.log('crashed!');
+	}
+	
+	
     this.orientation = orientation;
 
     this.flip = flip;