I always used to say to my wife the thing that I loved most about us is that we are a team we are impenetrable in that respect.

The future is hidden by a dark impenetrable veil and yet we struggle to pierce through it.

It's amazing that something only an atom thick can be an impenetrable barrier. You can have gas on one side and vacuum or liquid on the other and with a wall only one atom thick nothing would go through it.