Perhaps one of the most unusual and thought-provoking product lines that I have seen in years. Aaron has developed dozens of putty variations with interesting photonic, magnetic, viscous and thermally responsive properties. It is almost a new class of matter.
Be sure to check it out here.
The field of magnetorheology is an important one. Aaron has made a nanomagnetorheological viscous semifluid or thixotropic fluid, for us to play with.