Nim: paint: game underway; player 1's turn
Grid: showGrid: showGrid starts
Grid: getDimension: getDimension starts and ends
Square: showSquare: showSquare starts
Square: isEmpty: isEmpty starts and ends
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at Square.showSquare(Square.java:175)
	at Grid.showGrid(Grid.java:340)
	at Nim.paint(Nim.java:132)
	at java.awt.Container.update(Container.java:1988)
	at sun.awt.RepaintArea.updateComponent(RepaintArea.java:255)
	at sun.awt.RepaintArea.paint(RepaintArea.java:232)
	at sun.awt.windows.WComponentPeer.handleEvent(WComponentPeer.java:347)
	at java.awt.Component.dispatchEventImpl(Component.java:4937)
	at java.awt.Container.dispatchEventImpl(Container.java:2287)
	at java.awt.Window.dispatchEventImpl(Window.java:2713)
	at java.awt.Component.dispatchEvent(Component.java:4687)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
	at java.awt.EventQueue.access$000(EventQueue.java:101)
	at java.awt.EventQueue$3.run(EventQueue.java:666)
	at java.awt.EventQueue$3.run(EventQueue.java:664)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
	at java.awt.EventQueue$4.run(EventQueue.java:680)
	at java.awt.EventQueue$4.run(EventQueue.java:678)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)