diff --git a/examples/life.csn b/examples/life.csn
index 5507374..26a3375 100644
--- a/examples/life.csn
+++ b/examples/life.csn
@@ -1,14 +1,33 @@
 (
-    ; simple GOL with screen and a buffer
+    ; simple GOL with screen and a buffer + DRAWING!!!
+    
+    ; Middle-click to payse or resume 
+    ; (hold the button until paused - there is a sleep between generations and checking buttons)
+    ;
+    ; When paused, draw with left (white) and right (black) mouse buttons
+    ;
+    ; Resume by clicking middle again.
+    
+    (def GENERATION_MS 200)
 
+    ; Real pixel size
     (sc-init 400 400)
+    ; Upscaling factor (bug pixels)
     (sc-opt SCREEN_UPSCALE 10)
-    (sc-opt SCREEN_AUTO_BLIT 0)
+    
+    ; Number of big pixels
     (def W 40)
     (def H 40)
+    
+    ; !!! If you change size, also update the following constants.
+    ;     Compile-time math is not implemented yet.
+    
     (def XMAX 39) ; W-1
     (def YMAX 39) ; H-1
     (def NCELLS 1600) ; W*H
+        
+    ; --- end of config ---
+    (sc-opt SCREEN_AUTO_BLIT 0)
     
     (sc-erase 0) ; all black
     (sym ng g15)
@@ -27,13 +46,61 @@
     (bfwr @ng 95 1)
     (bfwr @ng 96 1)
     (bfwr @ng 97 1)
+    
+    
+    (def LBTN 0)
+    (def RBTN 1)
+    (def MBTN 2)
                 
     (:loop)
         (sc-poll)
-        ; TODO interactivity?
+        
+        ; Drawing
+        (sc-mbtn _ MBTN
+            (nz?
+                (:release)
+                    (sc-poll)
+                    (mslp 10)
+                    (sc-mbtn _ MBTN (nz? (j :release)))
+                    
+                (:mousing)
+                    (sc-poll)
+                    (mslp 10)
+                    
+                    (ld r3 -1)
+                    
+                    (sc-mbtn _ LBTN)
+                    (ld.nz r3 1)
+                    (sc-mbtn _ RBTN)
+                    (ld.nz r3 0)
+                    
+                    (tst r3 (nneg?
+                        (sc-mouse r0 r1)
+                        
+                        (tst r3)
+                        (sc-wr.nz r0 r1 #ffffff)
+                        (sc-wr.z r0 r1 #000000)
+                        
+                        (sc-blit)
+                        (mul r1 W)
+                        (add r0 r1)
+                        (ld8 r3:8 r3)
+                        (bfwr @ng r0 r3)
+                    ))                    
+                    
+                    (sc-mbtn _ MBTN 
+                        (z? (j :mousing)))
+                        
+                (:release2)
+                    (sc-poll)
+                    (mslp 10)
+                    (sc-mbtn _ MBTN (nz? (j :release2)))
+            )
+        )       
+        
         (call Display)
         (sc-blit)
-        (mslp 200)
+        (mslp GENERATION_MS)
         (j :loop)
     
     (proc CountNeighbors x y