diff --git a/agaric/templates/block/block--core.html.twig b/agaric/templates/block/block--core.html.twig
new file mode 100644
index 0000000..78f9798
--- /dev/null
+++ b/agaric/templates/block/block--core.html.twig
@@ -0,0 +1,8 @@
+{# See "@stable/block/block.html.twig" #}
+{# TODO probably let this go back to inheriting from Octavia/Bulma,
+   or include a pattern. #}
+<div {{ attributes }}>
+{% block content %}
+  {{ content }}
+{% endblock %}
+</div>