#!/usr/bin/env bash

p=3.14
i=0

reset () {
  /usr/bin/reset
  printf "\033[H\033[2J\033[0m"
  exit
}

trap "setterm --cursor on; stty echo; echo ${clear}; exit; trap -- - SIGINT SIGTERM" SIGTERM SIGINT
trap reset EXIT
trap reset SIGINT

stty -echo
setterm --cursor off

while true; do 
  i=$(bc -l <<< "$i+0.04")
  r=$(bc -l <<< "128+127*s($i)")
  g=$(bc -l <<< "128+127*s($i+$p*(1/3))")
  b=$(bc -l <<< "128+127*s($i+$p*(2/3))")
  printf "\033[48;2;${r%%.*};${g%%.*};${b%%.*}m\n"
  sleep .01
done