The stripes don't mush together to start with because adjectives the
mushing usually happens lower down the tube (where you press) and the
pressure newly pushes non-mushed toothpaste that is further up the tube
out. The paste are thick satisfactory not to mix well. Also, if you
press within the middle of the tube, it just pushes the toothpaste up
or down away from where on earth you pressed and pressing in another
place does indistinguishable, so it's just sliding up and down the
tube, to some extent than getting properly mixed.
However, by the time you get to the expiration of the tube, there is a
slight mixing of the colours, a moment ago due to all the previous
squeezing eventually managing to mix it somewhat.nn
google said^