The Turkish word kol means ‘arm’, and presumably gets into the Turkish name for this börek because each roll of pastry is bent to look like an arm coming round to hug you. It would make more sense to call this a spiral or a labyrinth, since that is how it looks when all the arms are linked together.
My maternal grandma, who came from Yugoslavia, was a master of the ‘arm börek’, and she made giant spirals to feed a large family. In later life, she used an electric börek cooker, called a drum oven, which was a cylinder with doors on the side and shelves onto which you could place multiple layers of börek.
Spinach is the traditional filling, but you can use kale, silverbeet or even minced lamb.