I don't know that these conform to the trademarked "Zentangle" lable... but I've been watching some of those YouTube videos and do find that they require sufficient concentration to escape from the mind monkeys that would otherwise torment me.
At the hotel breakfast, a mom was herding her toddler twins. Two year olds really are only "four heads" tall. These were rapid "in motion" sketches... but I'm glad I have a better understanding of their proportions. All head, hands and feet. NOT leggy!