Don't fill new grids unless we need it.

Also update places where it isn't needed.

src/Grid.java

@@ -9,15 +9,21 @@ public class Grid {
         _grid[0][0] = new Patch(this, 0, 0, 0);
     }
 
-    public Grid(int x, int y) {
+    public Grid(int x, int y, boolean fill) {
         _grid = new Patch[y][x];
-        for (int i = 0; i < x; i++) {
-            for (int j = 0; j < y; j++) {
-                _grid[j][i] = new Patch(this, i, j, 0);
+        if (fill) {
+            for (int i = 0; i < x; i++) {
+                for (int j = 0; j < y; j++) {
+                    _grid[j][i] = new Patch(this, i, j, 0);
+                }
             }
         }
     }
 
+    public Grid (int x, int y) {
+        this(x,y,true);
+    }
+
     private int normalizeX(int x) {
         while (x >= getWidth())
             x -= getWidth();

src/rules/BriansBrain.java

@@ -7,7 +7,7 @@ public class BriansBrain extends RuleSet {
     public static int states = 3;
 
     public static Grid run(Grid g) {
-        Grid newGrid = new Grid(g.getWidth(), g.getHeight());
+        Grid newGrid = new Grid(g.getWidth(), g.getHeight(), false);
         for (int i = 0; i < g.getWidth(); i++) {
             for (int j = 0; j < g.getHeight(); j++) {
                 Patch[] neighbors = g.getPatch(i, j).get8Neighbors();

src/rules/Conway.java

@@ -7,7 +7,7 @@ public class Conway extends RuleSet {
     public static int states = 2;
 
     public static Grid run (Grid g) {
-        Grid newGrid = new Grid(g.getWidth(), g.getHeight());
+        Grid newGrid = new Grid(g.getWidth(), g.getHeight(), false);
         for (int i = 0; i < g.getWidth(); i++) {
             for (int j = 0; j < g.getHeight(); j++) {
                 Patch[] neighbors = g.getPatch(i, j).get8Neighbors();

src/rules/Conway4.java

@@ -8,7 +8,7 @@ public class Conway4 extends RuleSet {
     public static int states = 2;
 
     public static Grid run (Grid g) {
-        Grid newGrid = new Grid(g.getWidth(), g.getHeight());
+        Grid newGrid = new Grid(g.getWidth(), g.getHeight(), false);
         for (int i = 0; i < g.getWidth(); i++) {
             for (int j = 0; j < g.getHeight(); j++) {
                 Patch[] neighbors = g.getPatch(i, j).get4Neighbors();

src/rules/LifeWithoutDeath.java

@@ -8,7 +8,7 @@ public class LifeWithoutDeath extends RuleSet {
     public static int states = 2;
 
     public static Grid run (Grid g) {
-        Grid newGrid = new Grid(g.getWidth(), g.getHeight());
+        Grid newGrid = new Grid(g.getWidth(), g.getHeight(), false);
         for (int i = 0; i < g.getWidth(); i++) {
             for (int j = 0; j < g.getHeight(); j++) {
                 Patch[] neighbors = g.getPatch(i, j).get8Neighbors();