Folks have already started experimenting with Instructable user mikey77’s silicone caulk / cornstarch mixture called “Oogoo.” This heart-shaped ice cube mold was made from the stuff by Briton Greg Tudor, who cast it around a polymer clay positive. A finished ice cube is to lower right.

Greg comments on his difficulties with the stiff consistency of the cornstarch / caulk mixture, which seems like an opportune time to mention a comment on last night’s Oogoo post from W. Aaron Waychoff, who claims to have had success using glycerine as an additive instead of cornstarch. [Thanks, Greg, and Aaron!]