These are really cool. I placed one in my reception area and it has been a huge hit. Everyone is amazed by it.
I remember seeing ferrofluid a few years back and thinking it was so cool. I love the science behind magnetic fields and I thought ferrofluid really shows off some of the cool patterns within them. This company makes a good product that lets me have all the joy of playing with ferrofluid and viewing it, without all the oily mess and hassle of containing it myself. I love that they cushioned the magnet on one side to keep it from harming the glass and that the ferrofluid stays a spiked ball at rest. Really neat product. (Packaged well, yadda yadda, this company does all the good stuff a company should.)
SPIKE ferrofluid display (Black ferrofluid)