Screenshots of the Arrowsmith web user interface that was employed by field testers during most of the two node searches described in this paper. This panel demonstrates a search to construct a list of diseases that are known to be characterized by the presence of both retinal detachment and aortic aneurysm, but not necessarily in the same patient (see Results). The AB and BC titles juxtaposed to each other. That is, titles containing both retinal detachment and Ehlers-Danlos are placed next to titles containing both Ehlers-Danlos and aortic aneurysm. Simple inspection of the titles confirms that Ehlers-Danlos syndrome is, indeed, characterized by both retinal detachment and aortic aneurysm. One can easily inspect other B-terms in the same manner.