A double Ferris wheel designed to include a horizontal turntable was patented in 1939 by John F. Courtney, working for Velare & Courtney. In Courtney's design, there were two independent Ferris wheels, each rotating at either end of a cantilever arm. The cantilever arm was supported in the middle by a tall vertical support, and the cantilever arm itself rotated around its middle pivot point. The design was similar to the earlier Aeriocycle, but the double wheel patented by Courtney allowed the cantilever arm to make a complete rotation, while the Aeriocycle was limited to a seesaw motion. Courtney continued to file additional patents on improved designs through the 1950s to make them more portable, and at about the same time, the Velare brothers patented the "Space Wheel", a side-by-side double with four total Ferris wheels.