The little brat has found three different ways to move axially on the ground. Moving laterally has not been a problem for the last few months since which he learned to roll over.

The three styles of protocrawling are:

• normal crawling: moving diagonally opposing hands/feet in unison

• leapfrogging: lifting body up, hopping both hands forward, catching up by dragging butt

• inchworming: pushing with butt, squishing the front and middle sections upward, then relaxing and allowing the front end to slip forward

Yes, it’s all trivial stuff to anyone with the flexibility of a few-month-old. But don’t try it with crispy aged adult joints if you know what’s good for you.