When I was a teenager with some mates we climbed through a small window into a public place with the lights out.
We got this glass and laid it out on a cast iron top.
Well this was very erie as the full moon was shining through this small window onto the glass.
We then , for a laugh ,all put our fingers onto the glass and used it like you do on s ouija board.
On deciding to stop there was a pause amongst us.
This perishing glass made a lovely squeaking noise all on its own on the cast iron and moved.
Pandemonium and panic , we all raced to the small window but 6 cannot get out all at once, the strongest got out first and brotherhood went out the "window."
No doubt there is a scientific reason yet to be proved of this glass action.
This is a true story and make your own minds up. And no , none of us moved the glass.