Martial Arts demonstration

Our Chinese New Year party for friends and family included a display of martial arts.  I used this photo to practice my drawing skills, as I am at the start of a course in life drawing.  I had hoped that using a photo instead of a live model would help me to get the ratios right.  The drawing was still a very rough approximation, probably because whenever ratio is mentioned my mathematical brain kicks in and the imprecision of using a thumb and pencil stirs up anxiety.