The Oreo cookie has been around for nearly 100 years. Since its introduction by Nabisco in 1912, its design has changed only a couple of times and the contemporary design we know today was settled upon way back in 1952.
The first pattern used was a simple wreath-like design, now it has a geometric pattern similar to a four-leaf clover, with a serated edge. Many sources credit William Turnier with this design, who worked for Nabisco as a design engineer during the time it was adopted. Below is a picture of the evolution of the cookie, on the left is what is looked like in 1912, in the middle is 1924, and on the right is what is looks like today.