These "Tullis" plots [Tullis et al. (1991), J. Geophys. Res., 96, 8081] give the strength on the horizontal of a mixture as a function of composition on the vertical axis, with both axes normalized from 0 to 1. Four idealized types of behavior are shown above. The plots at the right show types of actual behavior measured in our lab. Theory works well when the the two phases have nearly the same strength, not so well when the strength contrast is large (e.g., ice + sand). Other icy mixtures we have studied include ice + CO2 ice, ice + methane clathrate hydrate, and methane clathrate hydrate + sand.