#!/bin/sh

echo -n '['
for i in $(seq 0 2 255)
do
  echo -en "\e[38;2;0;$i;255m="
done
echo -e '\e[m]'

echo -n '['
for i in $(seq 0 2 255)
do
  echo -en "\e[48;2;0;$i;255m "
done
echo -e '\e[m]\n'

for i in $(seq 255 -6 0)
do
  for j in $(seq 0 3 255)
  do
    echo -en "\e[48;2;255;${j};${i}m "
  done
  echo -e '\e[m'
done