<!-- START of WP Query -->
<?php
$current_page = max( 1, get_query_var( 'paged' ) );
$the_query = new WP_Query( array(
    'post_type'      => 'post',
    'posts_per_page' => 10,
    'paged'          => $current_page,
    // other args here
) );

if ( $the_query->have_posts() ) :
    $count = 1;
    $posts = [];

    foreach ( $the_query->posts as &$post ) {
        $class = '';
        switch ( true ) {
            case ( 1 === $count ): $class = 'item1'; break;
            case ( $count < 5 ):   $class = 'item2'; break;
            case ( 9 === $count ): $class = 'item3'; break;
            // other conditions here
            default:               $class = 'item4'; break;
        }

        if ( ! isset( $posts[ $class ] ) )
            $posts[ $class ] = [];

        $posts[ $class ][] = $post;
        $count++;
    }

    $count = 1;
    foreach ( $posts as $class => $post_arr ) :
    ?>
        <div class="container">
            <?php
            foreach ( $post_arr as $post ) :
                setup_postdata( $post );
                ?>
                    <div class="item <?php echo $class; ?>">
                        <span>Post <?php echo $count; ?></span>
                        <?php the_title( '<h3>', '</h3>' ); ?>
                    </div>
                <?php
                $count++;
            endforeach; // end $post_arr
            ?>
        </div>
    <?php
    endforeach; // end $posts
?>
<style><!-- DEMO STYLES -->
.container { border: 1px solid #ccc; padding: 10px; margin: 10px; }
.item {
    display: inline-block;
    margin: 0 10px 10px -3px;
    padding: 10px;
    width: 25%;
    vertical-align: top;
}
.item1 { background: red; color: #fff; }
.item2 { background: orange; color: #fff; }
.item3 { background: yellow; color: #333; }
.item4 { background: green; color: #fff; }
</style>

<p>Pagination:</p>
<?php
    $big = 999999999; // need an unlikely integer
    echo paginate_links( array(
        'base'     => str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
        'format'   => '?paged=%#%',
        'current'  => $current_page,
        'total'    => $the_query->max_num_pages,
        'type'     => 'list',
        'end_size' => 3,
    ) );
?>
<?php else : ?>
    <p><?php esc_html_e( 'Sorry, no posts matched your criteria.' ); ?></p>
<?php endif;

wp_reset_postdata();
?>
<!-- END of WP Query -->