Juergen Hannappel wrote in
:


I'd like to see you (and hear) build a pea gravel castle...



Point taken - if they wish a sand stronghold, there's the neighborhood park
across the path with a hectare of sand!


When I was a little child I had no posh sandbox but an area of easy to
work muddy earth below a large hazel bush; shady, moist, and fun.


That's precisely my point...
I do reject your (guised) assertion that I'm deriving my children of some
sort of tactile, infantile right of passage!