I discuss the hammock plot for visualizing categorical or mixed categorical/numeric data. Hammock plots can be viewed as a generalization of parallel coordinate plots where the lines are replaced by boxes (or plotting elements) and the width of the boxes is proportional to the number of observations they represent. I also introduce a modification to the hammock plot to avoid what Hoffman et al. termed the reverse line width illusion. Further, I give an historical overview over hammock-type plots such as common angle, GPCP, parsets, and alluvial plots and discuss the type of boxes used to connect adjacent variables.