Toothpaste Tubes: The Mystery SquareThe engineering truth behind that colored block on the crimp.

From the show

Why it looks like that

Many household tubes feature a distinct colored rectangle on the sealed edge. While viral myths claim this code reveals chemical ingredients, the reality is pure engineering. This "eye mark" serves as a visual trigger for assembly line sensors, telling high-speed machines exactly where to cut and seal the tube so the branding stays perfectly centered.