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English: This is a form of light art that is produced with light emitting diodes (LEDs) on a hula hoop. It is pleasing visually and intellectually as there are several factors that produce the visual effect depicted. The first key to making the light patterns is the elliptical orbit. To illustrate, if the hula hoop was rolling on a conveyor belt, all of the LEDs would follow the same path. Initially the human eye would see the individual blinking LEDs in a circle but as the hoop increased speed, the light from the LEDs would appear as a narrow circle of light that would eventually blend together. The light artists can use all parts of their bodies to impart motion to the hoop. Just focusing on the forearm for a moment (since it can impart a large quantity of force on the hoop which translates to speed), the hoop orbits the forearm in an elliptical pattern, at times touching the arm and at times 3 feet (0.9 m) away from the arm. If we maintain a flat plane orbit by keeping the arm steady, we are able to perceive each of the LEDs along the circumference of the hoop, as shown in the image, which was taken in a Seattle park after experimenting with exposure times and viewing planes. As the LEDs turn on, remain on for a specific amount of time, and then turn off during each revolution, the lights appear to the human eye to produce impressions of objects. If the speed of the LED orbits change by changing the speed of the hoop, the objects can appear to move over time. The objects can also appear to move by changing when the LEDs are turned on or off. A common application of this concept is the apparent motion in a video on a computer screen. Another fun and useful application might be sending a time lapse message to astronauts by using four lights on Earth and either the Earth’s rotation or the orbital position of the Earth. Using the Earth’s rotation, four stationary lights in a vertical line could be individually turned on for a short amount of time during a set time interval, such as one hour as the Earth rotated. At the first hour mark, turning all four lights on for a moment would form the first vertical in an "H", then the next hour, only the second light would be turned on to form the horizontal bar on the "H". On the third hour, all four lights would be briefly turned on again to form the second vertical of the "H". At the fourth hour mark, lights 1, 3, and 4 would be turned on to form an "i". If astronauts in orbit recorded the lights on video and played back the video at high speed in a loop, which is analogous to observing the moving LEDs on the hula hoop, they would receive the message, "Hi".