If you go to Zaragoza this week, you will see many people wearing red and black checkered kerchief, which in Aragon is called cachirulo.
The red and black pattern is typical of Zaragoza, and it is worn for the Fiestas del Pilar, the celebrations in honor of the Virgin of the Pillar, patron saint of the city.
The traditional way of wearing a cachirulo (not just this pattern, but any patterned cachirulo) is from Muslim origin, men fold the square into a triangle and tie it around their head like so:
In more recent days, the red and black cachirulo is worn in a triangle, tied around the neck: