I first knew David from his papers on antimalarials, back when I was just starting work on this topic, which was some forty years ago!  Later on we worked on the same topic, structure and mechanism of Plasmodium dihydrofolate reductase, of which David developed a model, which turned out to be quite accurate compared to the X-ray structure we produced later.  His work taught me a lot, and I was happy to see and talk with him in person when we met in Geneva and other places.  I recall, not the meeting room itself, but the river and streets in Geneva where we spent long evenings window shopping and talking about things not necessarily concerning malaria.  It is a pity I don't have any pictures of these times, but they will always stay in my memory.