The visualization tool MARDIGRAS (Mass-Radius DIaGRAm with Sliders) enables simple and intuitive manipulation of mass-radius relationships (also known as iso-composition curves) using interactive sliders. It infers composition based on mass and radius (and other parameters). As a result, it requires use of actual measurements of mass and radius; values that are upper/lower limits, derived from empirical mass-radius relations, or are somewhat controversial should not be used. MARDIGRAS screen captures can be used for general scientific communication but are not of suitable quality for article publication.