function randomRange(minVal, maxVal) {
	
	return Math.floor(Math.random() * (maxVal - minVal - 1)) + minVal;
}

function clearContext(aContext)
{
	aContext.save();
	aContext.setTransform(1,0,0,1,0,0);
	aContext.clearRect(0, 0, canvas.width, canvas.height);
	aContext.restore();
};