JokingChicken

function b(
  a                  // placeholder
){
  return a           // if the placeholder was passed, return
    ? (              // a random number from 0 to 15
      a ^            // unless b is 8,
      Math.random()  // in which case
      * 16           // a random number from
      >> a/4         // 8 to 11
      ).toString(16) // in hexadecimal

JokingChicken

Colours in terminal

It's a common confusion about terminal colours... Actually we have this:

• plain ascii
• ansi escape codes (16 colour codes with bold/italic and background)
• 256 colour palette (216 colours + 16 ansi + 24 gray) (colors are 24bit)
• 24bit true colour ("888" colours (aka 16 milion))

printf "\x1b[${bg};2;${red};${green};${blue}m\n"