All of it.

chess/src/chess/Actor.java

@@ -6,4 +6,17 @@ abstract class Actor {
     Boolean inCheck;   // Whether the Actor is currently in check.
     Boolean canCastle; // Whether the Actor can castle.
     Boolean won;       // Whether the Actor has won.
+
+    Actor(Util.Col col, Boolean inCheck, Boolean canCastle, Boolean won) {
+        this.col = col;
+        this.inCheck = inCheck;
+        this.canCastle = canCastle;
+        this.won = won;
+    }
+
+    // Convenience constructor for start of game.
+    Actor(Util.Col col) {
+        this.col = col;
+        this.inCheck = this.canCastle = this.won = false;
+    }
 }

chess/src/chess/Bot.java

@@ -0,0 +1,6 @@
+package chess;
+
+// A chess bot.
+class Bot extends Actor {
+    Bot(Util.Col col) { super(col); }
+}

chess/src/chess/Game.java

@@ -1,6 +1,12 @@
 package chess;
 
-class Game {
+import javalib.impworld.*;
+
+class Game extends World {
     Actor white;
     Actor black;
+
+    public WorldScene makeScene() { return new WorldScene(0, 0); }
+
+    void run() { this.bigBang(0, 0, 0.01); }
 }

chess/src/chess/Main.java

@@ -1,3 +1,7 @@
 package chess;
 
-class Main {}
+import tester.Tester;
+
+class Examples {
+    void testItAll(Tester t) { new Game().run(); }
+}

chess/src/chess/Player.java

@@ -1,4 +1,6 @@
 package chess;
 
 // A human-controlled Actor.
-class Player extends Actor {}
+class Player extends Actor {
+    Player(Util.Col col) { super(col); }
+}