I have found many things but not this very trivial!
now i have visible this in movement - that is curious because my previous example seems make that!
1
2
3
4
3
2
1

i want visible in movement
1
12
1234
123
12
1

So how draw in up and undraw in down ?


i have refound it how to make that! :)

edit : sorry for the disturb!
So from now i can make some funny things with a minimum native nodes! :)

Maybe a last difficulty will be to find a variating axes changing inside the object at each step for thing like twist, rotation etc ...