private void placeIdentityDiscs() {
		while (getIdentityDiscCoverage() < coverage) {
			int randomX = (int) Math.round(Math.random() * grid.width);
			int randomY = (int) Math.round(Math.random() * grid.height);
			
			IdentityDisc idDisc = new IdentityDisc(new Position(randomX, randomY));
			if (grid.validPosition(idDisc.getPosition()) && canHaveAsIdentityDisc(idDisc)) {
				grid.addElement(idDisc);
				
				factory.addObservable(idDisc);
			}
		}
	}