Blood clots have long been implicated in heart attacks and strokes. While the role of one key protein, called von Willebrand factor, has been established, a reliable model for predicting how it collects in blood vessels remains elusive. Researchers review recent work on understanding the behavior of vWF in APL Bioengineering, painting a portrait of vWF, and by highlighting advances in the field, the authors put forth promising avenues for therapies in controlling these proteins.