Implement Conway, add states variable to ruleset.

src/rules/Conway.java

@@ -4,13 +4,30 @@ import edu.stuy.goldfish.Grid;
 import edu.stuy.goldfish.Patch;
 
 public class Conway implements RuleSet {
-
-    public Conway () {
-        Patch p = new Patch();
-    }
+    states = 2;
 
     @Override
     public static Grid run (Grid g) {
-        return g; //TODO: do stuff.
+        Grid newGrid = new Grid(g.getWidth(), g.getHeight());
+        for (int i = 0; i < g.getWidth(); i++) {
+            for (int j = 0; j < j.getHeight(); j++) {
+                Patch[] neighbors = g.getPatch(i, j).get8Neighbors();
+                int numAlive = 0;
+                for (Patch p : neighbors)
+                    if (p.getState() == 1) numAlive++;
+                Patch p = g.getPatch(i,j).clone();
+                if (numAlive < 2) {
+                    p.setState(0); //Dies by underpopulation
+                }
+                if (numAlive > 3) {
+                    p.setState(0); //Dies by overpopulation
+                }
+                if (numAlive == 3)
+                    p.setState(1); //Born with 3 neighbors.
+                newGrid.setPatch(i,j,p);
+            }
+        }
+        return newGrid;
     }
+
 }

src/rules/RuleSet.java

@@ -3,6 +3,7 @@ package edu.stuy.goldfish.rules;
 import edu.stuy.goldfish.Grid;
 
 public interface RuleSet {
+    public static int states;
 
     /**
      * Run this ruleset on a grid, returning the result.
@@ -13,5 +14,4 @@ public interface RuleSet {
      */
     public static Grid run (Grid g);
 
-
 }