I see what happened. The cogwheel isn't there after going into full screen with the full-screen icon that appears on the screen during playback: but it is there if I use the YouTube full-screen icon that's in the lower control panel, as you've explained. Got it! Thank you for your help, Dr. Sassi!

Could anyone please tell me how I can change the playback speed of tutorials on Cineversity? For example, to playback at 1.5x or 2x? I don't see a pop-up or anything, but I must be just missing it. Thanks!