From project description:
SkyDelta is a new style of open-source RepRap 3D printer. Similar to deltabots like the Kossel, Rostock, Cerberus, Wolfstock, and many others, it has a triangular-prism frame. However, instead of using linear rails and rigid rods to move the print head through space, SkyDelta employs tensioned lines.
Detailed post about SkyDelta: