ANTIC OPTICAL ILLUSION CHALLENGE

Can you emulate the Lightstick?

They're called Lightsticks and they're on display at places like Disneyland's Videopolis and San Francisco's Exploratorium. The Lightstick produces one of the cleverest optical illusions around. The creator of the Lightstick says its illusion cannot be duplicated on a personal computer. So here's an Antic challenge: Can you create the Lightstick Illusion on your 8-bit or ST Atari computer?

At first glance, the Lightstick looks like nothing more than a six-foot-high column of blinking red LEDs (light emitting diodes) flashing against a black background. The LEDs are flashing thousands of times every second, so fast that the column appears to be merely a vertical red light that's flickering a bit.

Look directly at the Lightstick and you'll see nothing special. But look past it, or turn your head away, and images appear to spring from that column of LEDs. There are pictures, banners, slogans-all in red-and they appear to hang momentarily in the air.
   The images look something like bright red high-resolution graphics pictures, and they're formed in the same way as a picture on your Atari video display. Each of the Lightstick's hundreds of LEDs is individually controlled, flashing on and off in accordance with patterns stored in the Lightstick's memory. Each fraction of a second, the LEDs flash a very narrow vertical slice of the picture-like one vertical column on a computer's screen. It's impossible to tell what a picture is if you just see one column at a time.

Bill Bell, the Boston designer who created the Lightstick, says the effect depends on several things. One is very bright LEDs flashing very fast (some Lightsticks have more than one LED for each horizontal row of the column, to make the image brighter). Another essential is a dark background. A third is rapid eye movement and peripheral vision; you can't see the images by looking directly at the Lightstick.

THE CHALLENGE
We'd like to see you try to emulate the Lightstick on your Atari-and we think Antic readers would like to see the results of your efforts. We'd also like to see what other kinds of optical illusions you can create using your Atari.
   Send Antic your pictures and programs on disk. If we publish your Atari Illusion, we'll send you a graphics software disk from the Antic Catalog. The editors' choice of best Atari Illusion received in 1986 will win its creator a one-year Antic disk subscription. And if we publish your full-length Atari Illusion program, you'll be paid for it at our standard authors' rate.

Your Atari Illusion can be color or monochrome, in any ST resolution or 8-bit graphics mode. Include a short letter with your name, address, phone number and any necessary instructions for running your images. All entries become the property of Antic Publishing, Inc. and cannot be returned. Send your computerized illusions to: Illusion Challenge, Antic, 524 Second Street, San Francisco, CA 94107 and show the world just how much more there is to your Atari than meets the eye.