Exercise : well you guessed it this time, you won't make the room you will make... whatever the heck you want. By now you should have an entire palette of colors, size, primitives of course but also assets, from images to video, from flat to 360, from curved images (yes... we didn't try that yet but it's possible and relatively easy) so bring it all back, make the most original, creative or just mad patchwork you can think of.
Note : if you want to use assets from other website link to them directly. If it does not work upload a copy on https://learnwebvr.xyz/upload/AirbusJune2017/ . Please don't ask why it doesn't work in the first place it's a terribly boring topic, trust me you don't want to know. If you really want to know ... check CORS - a guided tour.
Extra exercise : Write down what's missing, again. It's nice to have all those elements around you but is that enough? What would make immersion better?
Exercise : Go through http://jsbin.com/boyefi/edit?html,output and explain as comments LINE BY LINE what is happening. If you need it also load the image or mesh of a duck cf Rubber duck debugging.