More improvements to automata slide.

src/slide/s4_automata.rs

@@ -160,15 +160,20 @@ impl Slide for Automata {
                         // Automatically begin expansion.
                         *expanding = true;
                     } else if *iterations == 20 {
-                        // Draw a line to create a cool pattern.
+                        // Draw a vertical line on the left to create a cool pattern.
                         for y in 4..self.life.size_cells - 4 {
                             self.life.set_fill(2, y, Color32::BLACK);
                         }
                     } else if *iterations == 30 {
-                        // Draw another line to create a cool pattern.
+                        // Draw another set of lines to create a cool pattern.
                         for x in 4..self.life.size_cells - 4 {
+                            // Solid line at the bottom.
                             self.life
                                 .set_fill(x, self.life.size_cells - 2, Color32::BLACK);
+                            // Line with gaps at the top.
+                            if x % 6 != 0 {
+                                self.life.set_fill(x, 2, Color32::BLACK);
+                            }
                         }
                     }