toothpaste stripes

The stripes in toothpaste are created by a special device fitted to the nozzle end of the tube. A colored toothpaste is first filled around the special fitting, the white toothpaste is filled second, which holds the colored toothpaste in place at the top of the tube. When the tube is squeezed, the white toothpaste would run through the special inner tube and the pressure of the squeeze simultaneously forces the colored toothpaste through the tiny orifices at the end. The toothpaste emerges perfectly striped.