private void placeLightGrenades() {
		while (getElementCoverage(LightGrenade.class) < COVERAGE) {
			final Position randomPos = getRandomPosition();
			final LightGrenade lg = createLightGrenade();
			if (grid.validPosition(randomPos) && canHaveAsElement(randomPos, lg))
				grid.addElementToPosition(lg, randomPos);
		}
	}