public void setLowerThresholdVisible(final boolean VISIBLE) {
        if (null == lowerThresholdVisible) {
            _lowerThresholdVisible = VISIBLE;
            fireTileEvent(VISIBILITY_EVENT);
        } else {
            if (!lowerThresholdVisible.isBound()) {
                lowerThresholdVisible.set(VISIBLE);
            }
        }
    }
Defines if the lower threshold indicator should be drawn

@param VISIBLE
src/main/java/eu/hansolo/tilesfx/Tile.java