I noticed something this evening while doing Baguazhang mud walking in a straight line. Basically it is the same as the Xingyiquan Chicken step, just less jumpy than most styles of Xingyiquan. However, Wudang Xingyiquan does train a step that is exactly the same as mud walking and it does it straight, 90 degree stepping and circular. As well as training your typical Xingyiquan chicken step. Just found that interesting, and after 25 years of Chinese martial arts, most of that labeled Neijia (internal) it was a real big "Well Duh!!!" moment too.