collatzyboi.php

<?php
if (isset($_GET["base"]))
    $const = intval($_GET["base"]);
else $const = 2;
if (isset($_GET["brightness"]))
    $brightness = intval($_GET["brightness"]);
else $brightness = 1500;
?>
<title>col(n,<?=$const;?>)</title>
<body bgcolor="black" style="color: white">
<?php
function col ($n, $b = 2) {
    return ($n % $b == 0) * ($n/$b)
         + ($n % $b >  0) * ($n+intval($n/$b)+1);
}
$maxi = 0;
$array = [];
for ($i = 1; $i < 10000; $i++) {
    $m = $i;
    while (!in_array($m,$array)) {
        $array[count($array)] = $m;
        $m = col($m,$const);
    }
}
foreach ($array as $i => $e) {
    print "<div style='position: absolute; left: ".(10+array_search(col($e,$const),$array)/10)
                                       ."; bottom: ".(10+col($e,$const)/10).";
    color: rgba(".($brightness/$e*255).",0,0,0.5)'>.</div>\n";
}
?>
<form method="get">
Base : <input type="text" name="base" value="<?=$const;?>"><br>
Brightness : <input type="text" name="brightness" value="<?=$brightness;?>"><br>
<input type="submit">
</form>