{{ base_var }}

base2 template

{% block title %}block title in base2, should be hidden by main template{% endblock %}
{% block title2 %}block title2 in base2, should be hidden by base1{% endblock %}

more of base2 template

{% block content %}block content in base 2, should be overwritten{% endblock %}

{% block content2 %}block content2 in base 2, should pass through{% endblock %}

end of base2 template