Algae with rules

(namespace ‘
    (a http://www.w3.org/2000/10/annotation-ns#)
    (h http://www.w3.org/2002/04/26-face#)

ask '(
    (a::annotates ?annot http://example.com/page.html)
    (bm::hasTopic ?annot h::head)
    (?property ?annot ?value))
:collect ‘(?annot ?property ?value))