directives -> language-version <1.1>, namespace ; engineering -> Maker's Muse [https://www.youtube.com/user/TheMakersMuse] , Jared Owen [https://www.youtube.com/user/captainranic] , ENGINEERING TODAY [https://www.youtube.com/channel/UCaC97sX6xzQKvPLkZ9AbC-A] , Curious Elephant [https://www.youtube.com/channel/UCZUlf2TKB8vATuo5-s1N-5Q] , Mark Rober [https://www.youtube.com/user/onemeeeliondollars] <3vUyd3Jc>, The Thought Emporium [https://www.youtube.com/user/TheChemlife] , Real Engineering [https://www.youtube.com/channel/UCR1IuLEqb6UEA_zQ81kwXfg] , styropyro [https://www.youtube.com/user/styropyro] , Be Smart [https://www.youtube.com/user/itsokaytobesmart] , Veritasium [https://www.youtube.com/user/1veritasium] , Curious Droid [https://www.youtube.com/channel/UC726J5A0LLFRxQ0SZqr2mYQ] , Smarter Every Day 2 [https://www.youtube.com/user/FunnerEveryDay] <8vO93bNW>, SmarterEveryDay [https://www.youtube.com/user/destinws2] , Vsauce [https://www.youtube.com/user/Vsauce] , Integza [https://www.youtube.com/channel/UC2avWDLN1EI3r1RZ_dlSxCw] ;