n0.setContent(new_node_content);
if (content_features(n0.getContent()).liquid_type == LIQUID_FLOWING) {
// set level to last 3 bits, flowing down bit to 4th bit
n0.setContent(new_node_content);
if (content_features(n0.getContent()).liquid_type == LIQUID_FLOWING) {
// set level to last 3 bits, flowing down bit to 4th bit