public ManaCrystal getClosestCrystal(Point point) {
		double min = Double.POSITIVE_INFINITY;
		ManaCrystal closestManaCrystal = null;
		for(ManaCrystal manaCrystal : manaCrystals) {
			if(manaCrystal instanceof ManaCrystal) {
				if(Geometry.squareDistance(point, manaCrystal.getPoint()) < min) {
					min = Geometry.squareDistance(point, manaCrystal.getPoint());
					closestManaCrystal = manaCrystal;
				}
			}
		}
		return closestManaCrystal;
	}