So what do you do when you are the largest fast food provider in the world and you have just invented a layered two flavor shake that needs to have those flavors mix while eating? You hire a bunch of aerospace engineers to design a new straw for you, and that is exactly what McDonald’s did for the new Chocolate Shamrock Shake, one of four new seasonal McCafé beverages.

The new McCafé beverage has dual layers of chocolate shake below mint Shamrock Shake, and the new recipe presented McDonald’s with a unique challenge. How do you deliver the ideal flavor ratio of 50% chocolate and 50% mint in each sip, versus enjoying each flavor separately with a traditional straw. To solve the problem McDonald’s turned to highly-qualified engineering firms. JACE and NK Labs created the probably-more-revolutionary-than-actually-needed Suction Tube for Reverse Axial Withdrawal straw. The STRAW’s j-shape provides optimal flavor flow dynamics.

Due to the STRAW’s unique design, only 2,000 were produced in time for Shamrock Shake season and it will only be available in select participating restaurants with the purchase of a Chocolate Shamrock Shake. Visit mcdonalds.mwnewsroom.com/US to learn where and when the lucky few will be distributed. (I don’t want the shake, but I definitely want the straw). And, like the seasonal offering of the McCafé Shamrock Chocolate offerings, the STRAW is also available for a limited time.

“It was a puzzling assignment but one with an ambitious goal,” said Seth Newburg, principal engineer and managing partner at NK Labs. “From a physics perspective, it’s actually quite difficult to deliver a proportional amount of both chocolate and mint flavors with each sip. But that’s exactly what we did. It’s a marvel of fluid dynamics. Thanks Fibonacci sequence.”