public void jumpChecker(Checker marked) {
		//Find piece to jump.
		for (int i = 0; i < pieces.size(); i++) {
			if (pieces.get(i).getX() == marked.getX() &&
					pieces.get(i).getY() == marked.getY() &&
					!pieces.get(i).sameColor(marked)) {
				pieces.remove(i);
				return;
			}
		}
	    
		//Board is invalid.
		valid = false;
	}