Inventor Benjamin Krempel says it is like squeezing toothpaste from a tube.

She was squeezing toothpaste on to a brand-new toothbrush when Jack knocked on the bedroom door.

And it usually moves slowly, like squeezing toothpaste down a hill - but it will get there eventually.

In the bathroom, the Yattering would have squeezed toothpaste around the toilet-seat and have plugged up the shower-head with soggy toilet-paper.

If genome editing was once akin to performing dental surgery, it had almost overnight become more like squeezing toothpaste out of a tube.