Freestyle NinjaJune 14, 2016 CORE GTS4 - Freestyle Ninja. Megaloop Machine. And more. from CORE Kiteboarding on Vimeo. Sofia Moraes, Steven Akkersdijk, Willow-River Tonkin, and Philipp Zach explore South Africa on CORE’s newest member of the Universal+ Series: The indomitable GTS4.