<?php
header("Content-Type: text/plain; charset=utf-8");
?> 
<?php

error_reporting(-1);
mb_internal_encoding('utf-8');
$text = 'В российском сегменте очень';


$len          = mb_strlen($text);
$circleRadius = $len / 2.5;

$text     = explode(' ', $text);
$newArray = array();
foreach ($text as $v) {
    $newArray[] = preg_split("//u", $v, null, PREG_SPLIT_NO_EMPTY);
    
}
$txt = array();
foreach ($newArray as $v) {
    foreach ($v as $letter) {
        $txt[] = $letter;
    }
}

$probels = array();
for ($i = 0; $i <= $len * 4; $i++) {
    for ($k = 0; $k <= $len * 4; $k++) {
        $probels[$i][$k] = ' ';
    }
    
}

$corners = array();
$corner  = number_format(360 / $len, 2);
$c       = $corner;


$i = 0;
foreach ($txt as $letter) {
    
    $x = (round(cos($c * M_PI / 180) * $circleRadius) + $circleRadius) * 2;
    $y = round(sin($c * M_PI / 180) * $circleRadius) + $circleRadius;
    $probels[$y][$x] = $letter;
    
    $c += $corner;
    
}
foreach ($probels as $v) {
    foreach ($v as $val) {
        echo $val;
    }
    echo "\n";
}