Regarding HDMI cable quality, that is a touchy subject. I always smile when I hear the "It's 1's and 0's" argument: usually employed in defending a purchase of a lower priced HDMI cable. HDMI signals are transmitted via micro electrical currents and as such can be affected by EMI/RFI which in turn can effect audio and video quality.
Makes me smile too
That makes me smile too
First, in the digital world, you can't find a signal looking like that. Second, even if it would be, the irony is that what you sketched will still work since you drew a 1 being at the same level as your good cable and your rise/fall time being identical. Maybe you should draw something that actually wouldn't work