No actual content here, sites that facinated me about USB-C PD, where the cc line acts as both power negotiation and host-client negotiation, and that this can be reversed mid charge.
Another interesting thing is how usb 3.1 and above use backwards compatibility to their advantage. Where usb 3.0 type A only use the D+ and D- of the usb lines (ones used for usb 2.0) to initialize usb 3.0 communication through the TX+, TX- and RX+, RX- lines, usb 3.2 type c will use both the D+, D-, and tx+, tx-, rx+, rx- line for even faster performance! and using cc lines, D+ and D- can manage display output without affecting the tx/rx pair transfer speeds.
References
https://superuser.com/questions/1213263/why-does-usb-3-1-only-use-two-of-the-four-available-data-lines https://www.chipestimate.com/partner_docs/USB_Type-C_Challenge_for_SoC_Designers_WP.PDF