Focus stacking - Marmite

I'm just putting together a new lecture called 

"Angles of view, perspective, depth of field, and all that confusing, complicated stuff ...

... made simple"

and one of ways I show how limited depth of field is on close up subjects is shown in this photo. The top image is a single shot at f11 - at the distance in the photo, has hardly any depth of field - but is the first image of a focus stack. 

The lower part of the photo shows the completed focus stack, a combination of 60 pictures which were needed to get the depth of field wide enough to encompass the whole of the writing on the jar when angled as it is. 

Extra shows how close the camera was to the subject