Okay, I can visualize that. Cut out the passageway in the hourglass and you have a bottle of sand which isn't moving. But you would have to also say that the future and past is but one substance, like a carton of Morton's Salt.
(As an aside, I view tipping over the hourglass to start anew is a perfect analogy for the biblical 'new dispensation of time.' But who or what does the tipping?)
(Hi, AG! Just wanted to wave atcha.)
Hi Eastbound! So good to see you!