diff --git a/falling_sand.py b/falling_sand.py
old mode 100644
new mode 100755
index d883e8d..676e291
--- a/falling_sand.py
+++ b/falling_sand.py
@@ -25,6 +25,7 @@ class FallingSandParticle:
         self.not_moving = 0
 
         x, y = start_pos
+
         self.app.matrix[x, y] = self.color
 
     def update(self):
@@ -79,12 +80,13 @@ class FallingSandParticle:
 
                 return
 
-        self.not_moving = 0
+        if not x > self.app.sand_surface.get_width() - 2:# and not x < 0:
+            self.not_moving = 0
 
-        self.pos = (x, y)
+            self.pos = (x, y)
 
-        self.app.matrix[ox, oy] = self.app.gray
-        self.app.matrix[x, y] = self.color
+            self.app.matrix[ox, oy] = self.app.gray
+            self.app.matrix[x, y] = self.color
 
 
 class FallingSand:
@@ -206,7 +208,7 @@ class FallingSand:
                 bx += ax
                 by += ay
 
-                if self.matrix[bx, by] == self.sand_surface.map_rgb(self.gray) and bx % 2 == 0 and by % 2 == 0:
+                if not bx > self.sand_surface.get_width() - 2 and self.matrix[bx, by] == self.sand_surface.map_rgb(self.gray) and bx % 2 == 0 and by % 2 == 0:
                     self.falling_sand_particles.append(FallingSandParticle(self, (bx, by), color))
 
     def rainbow(self):