Perpetual motion

October 1920 issue of Popular Science magazine,
on perpetual motion. Although considered impossible
 by scientists, perpetual motion continues to capture
 the imagination of inventors. The device shown is
 a "mass leverage" device, where the spherical weights
 on our right have more leverage than those on the left,
supposedly creating a perpetual rotation, but there
 are a greater number of weights to our
left, balancing the device.

Perpetual motion describes hypothetical machines that operate or produce useful work indefinitely and, more generally, hypothetical machines that produce more work or energy than they consume, whether they might operate indefinitely or not.

Apple Lisa

Apple Lisa, with an Apple ProFile external hard disk sitting atop it.
Note the dual 5.25-inch "Twiggy" floppy drives.

The Apple Lisa was a personal computer designed by Apple Computer, Inc. (now Apple, Inc.) during the early 1980s.

The Lisa project was started at Apple in 1978 and evolved into a project to design a powerful personal computer with a graphical user interface (GUI) that would be targeted toward business customers.

Aircraft Ejection Seats.

United States Air Force F-15 Eagle ejection seat test using a mannequin

In aircraft, an ejection seat is a system designed to rescue the pilot or other crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rocket motor, carrying the pilot with it.

Fresnel lens

Lighthouse Fresnel lens, on display at the Musée national de la Marine

A Fresnel lens (pronounced /freɪˈnɛl/ fray-NELL) is a type of lens originally developed by French physicist Augustin-Jean Fresnel for lighthouses.

The design enables the construction of lenses of large aperture and short focal length without the mass and

What Is HTML5?

HTML5: Everyone’s using it, nobody knows what it is. I realize that sounds more like a line out of an existential movie — maybe Waiting for Godot or a screenplay by Sartre — than a statement about HTML5. But it’s really the truth: most of the people using HTML5 are treating it as HTML4+, or