At a point where three or more bubbles meet, they sort themselves out so that only three bubble walls meet along a line.

Do both universes have their own "bubble wall", so they just collide and bounce away from each other?

She's calling something to us, but I can't hear her through the bubble wall.

I'm watching the sun rise through the bubble wall.

There was movement, a wash of light beyond the bubble wall.

The ship always crossed the bubble walls at some thin spot.

Radiation could only be generated in collisions between bubble walls.

Note that despite being in direct contact with a nuclear explosion, the water of the expanding bubble wall does not boil.

They never expected him to run his vehicle through the bubble wall.

To her right was the curve of the bubble wall.