The curvature and torsion: how to distinguish the shape of a curve 
Stereoscopy
This app was designed to be viewed in stereoscopy, allowing a three-dimensional visualization of the represented objects. Stereoscopy viewing requires a stereoscopy kit whose purchase is available on the Atractor Association website. The website contains other stereoscopic content (for now, only in Portuguese).
In case you cannot see these apps in stereoscopy, double-click on s key to get a plane version of the apps (the advantage of this version is that the objects represented therein do not appear in duplicate).
