Toothpaste

[kezgal]

How do the blue and white stripes 'stay stripey' in a tube of toothpaste, without mixing together?

[CheekyChops]

From the Discovery Channel's website:

Striped toothpaste is made by having pastes of two colours contained within separate chambers in the packaging. Squeezing the tube pushes the paste through separate parts of the nozzle, creating the striped effect.

[heathfield]

For example