odoo_theme/theme_treehouse/theme_common/views/s_menu_three_columns.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <template name="3 Col Menu" id="s_menu_three_columns">
        <section class="s_menu_three_columns">
            <div class="container three-column">
                <div class="row">
                    <div class="col-lg-4 big-menu bg-beta">
                        <h2 class="text-center"><a href="#">Take a tour</a></h2>
                    </div>
                    <div class="col-lg-4 big-menu bg-gamma">
                        <h2 class="text-center"><a href="#">Take a tour</a></h2>
                    </div>
                    <div class="col-lg-4 big-menu bg-delta">
                        <h2 class="text-center"><a href="#">Take a tour</a></h2>
                    </div>
                </div>
            </div>
        </section>
    </template>
</odoo>