diff --git a/conway.lua b/conway.lua
index 64565e4..effd5e4 100644
--- a/conway.lua
+++ b/conway.lua
@@ -12,9 +12,10 @@ for i=0,width*height-1 do
 	buffer[i]=0
 end
 -- initial state
-buffer[11+10*width]=1
-buffer[12+10*width]=1
-buffer[13+10*width]=1
+math.randomseed(1234)
+for i=0,2500 do
+	buffer[math.random(0, width*height-1)]=1
+end
 
 function display()
 	for y=0,height-1 do
@@ -29,18 +30,16 @@ function display()
 end
 
 function compute_ib()
- for i=0,width*height-1 do
-		ib[i]=buffer[i]
-	end
+	ib[0]=buffer[0]
 	for x=1,width-1 do
-		ib[x]=ib[x]+ib[x-1]
+		ib[x]=buffer[x]+ib[x-1]
 	end
 	for y=1,height-1 do
-		ib[y*width]=ib[y*width]+ib[(y-1)*width]
+		ib[y*width]=buffer[y*width]+ib[(y-1)*width]
 	end
 	for y=1,height-1 do
 		for x=1,width-1 do
-			ib[x+y*width]=ib[x+y*width]+ib[x-1+y*width]+ib[x+(y-1)*width]
+			ib[x+y*width]=buffer[x+y*width]+ib[x-1+y*width]+ib[x+(y-1)*width]-ib[x-1+(y-1)*width]
 		end
 	end
 end
@@ -57,7 +56,7 @@ function update()
 				buffer[i]=0
 			elseif n == 3 then
 				buffer[i]=1
-			else
+			elseif n > 3 then
 				buffer[i]=0
 			end			
 		end
@@ -66,10 +65,7 @@ end
 
 function TIC()
 	display()
-	if btn(0) then update() end
-	if btn(1) then update() end
-	if btn(2) then update() end
-	if btn(3) then update() end
+	if t%30==0 then update() end
 	t=t+1
 end