function NumberRabbit(aName){

	/* instance variables and default values */
	this.id = aName
	this.position = 0
	
		
	/* accessor methods (directly access instance variable) */
	this.getPosition = function(){return this.position}
	this.setPosition = function(aNumber){this.position = aNumber; updateIcon(this.id, this.position)}
	
	
	/* other instance methods */
	this.left = function(){this.setPosition(this.getPosition() - 1)}
	this.right = function(){this.setPosition(this.getPosition() + 1)}
	this.reset = function(){this.setPosition(0)}
	this.plus = function(aRabbit1, aRabbit2){this.setPosition(aRabbit1.getPosition() + aRabbit2.getPosition())}
	this.times = function(aRabbit1, aRabbit2){this.setPosition(aRabbit1.getPosition() * aRabbit2.getPosition())}
	
	
	/* helper method - for dealing with HTML interface */
	function updateIcon(aName, aNumber){document.getElementById(aName).style.left = aNumber*50 + 12}
	
}