awk 'BEGIN {
  s="/\\/\\/\\/\\/\\"; s=s s s s s s s s;
  for (colnum = 0; colnum<77; colnum++) {
    r = 255-(colnum*255/76);
    g = (colnum*510/76);
    b = (colnum*255/76);
    if (g>255) g = 510-g;
    printf "\033[48;2;%d;%d;%dm", r,g,b;
    printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
    printf "%s\033[0m", substr(s,colnum+1,1);
  }
  printf "\n";
}'