fork download
<?php
$clientes = array(
array(
    "nome" => "Cliente 1",
    "categoria" => "Turismo",
    "logo" => "turismo.jpg"
),
array(
    "nome" => "Suporte",
    "categoria" => "Tecnologia",
    "logo" => "suporte.jpg"
),
array(
    "nome" => "Faculdade Futura",
    "categoria" => "Educação",
    "logo" => "faculdade-futura.jpg"
));
$tmp = $clientes;
shuffle(array_slice(tmp, 15, count($clientes) - 15));
$novo = array_merge(array_slice($clientes, 0, 15), array_slice($tmp, 0, 30));
foreach ($novo as $atributo => $valor):
   echo "{$valor["nome"]}\n";
endforeach;

//https://pt.stackoverflow.com/q/345270/101
Success #stdin #stdout #stderr 0s 82560KB
stdin
Standard input is empty
stdout
Cliente 1
Suporte
Faculdade Futura
Cliente 1
Suporte
Faculdade Futura
stderr
PHP Notice:  Use of undefined constant tmp - assumed 'tmp' in /home/TNVJL7/prog.php on line 19
PHP Warning:  array_slice() expects parameter 1 to be array, string given in /home/TNVJL7/prog.php on line 19
PHP Notice:  Only variables should be passed by reference in /home/TNVJL7/prog.php on line 19
PHP Warning:  shuffle() expects parameter 1 to be array, null given in /home/TNVJL7/prog.php on line 19