Integrity is doing the right thing

even when no one is watching

The mysery of the moving stones !! Not as big a question as the stonehenge issues I realise, however just as puzzling. These stones (well pebbles) are just at the bottom of our garden step. We do not put them there. In fact they are swept on a slightly regularish basis away from here because when we walk around barefoot - they are right in the way. So why do they keep coming back??? The small slug isn't anything to do with the situation I just didn't notice he was there !!
Any stone theorists out there? We have watched ....... gets quite boring and they don't move all in one go, just gradually over a week or so, until there is a collection like this.
Can ants shift them?. When we move them away there is no hole underneath just the grit that is in the gap between the paving slabs. This little lot has taken two weeks to return.
No children are involved, because take my word for it , they are NOT interested and it's already gone on the 'Mum's getting old and slightly potty list !!'
So apart from setting up a covert camera - which does seem slightly extreeme!! I wondered if anyone has any ideas.

Early bedtime to get up early for a few days away won't be blipping until I get back. I am going to ignore the internet completely!!!! Well try anyway. Have a good weekend everyone.