 
 (defun timeline-tools-entry-category (entry)
   "Return ARCHIVE_CATEGORY or CATEGORY at position given by MARKER.
-Return whatever is found first.  ENTRY can be a plain timeline
-entry or a cluster."
-  (let ((marker (car (timeline-tools-entry-marker entry))))
+Return whatever is found first."
+  (let ((marker (car (timeline-tools-entry-markers entry))))
     (or (org-entry-get marker "ARCHIVE_CATEGORY")
         (org-entry-get marker "CATEGORY"))))
 

              (timeline-tools-make-entry
               (timeline-tools-entry-start-time (-first-item cluster))
               (timeline-tools-entry-end-time (-last-item cluster))
               (-mapcat #'timeline-tools-entry-marker cluster)))
            new-timeline)))

(defun timeline-tools-skip-short-entries (timeline)

(defalias 'timeline-tools-entry-end-time 'cadr
  "End time of ENTRY.")

(defalias 'timeline-tools-entry-markers 'caddr
  "Marker to org task of ENTRY.")

(defun timeline-tools-make-entry (start-time end-time markers)
