#!/usr/bin/perl -w

use strict;

my $pi = 2 * atan2(1, 0);

for (0..255) {

# limit from blue to red

my $n = (255 - $_) * 2 / 3;

# phase adjust

my $r = ($n + 255 * 1 / 3) % 256;

my $g = ($n + 255 * 0 / 3) % 256;

my $b = ($n + 255 * 2 / 3) % 256;

# convert to sinusoid

$r = $r <= 256 * 2 / 3 ? (1 - cos(3 * $pi * $r / 256)) / 2 : 0;

$g = $g <= 256 * 2 / 3 ? (1 - cos(3 * $pi * $g / 256)) / 2 : 0;

$b = $b <= 256 * 2 / 3 ? (1 - cos(3 * $pi * $b / 256)) / 2 : 0;

# convert float to char

$r = int($r * 256);

$g = int($g * 256);

$b = int($b * 256);

printf "%03d %03d %03d\n", $r, $g, $b;

}