In big bowl mix butter,salt,sugar and flour until it forms soft dough.

Now make three parts of it and add color. Keep it in fridge for 1 hour to rest. Then roll three round 1/5 inch thickness and as shown in pic arrange them in order.

Now,roll it to cylinder shape and let it rest in fridge for 30 mins more.

Once it is cooled,cut them in shape and bake it in over for 15 mins at 170 degrees. You can roll them into sprinkles on for different texture.