Robur is a very original expander

To work effectively, the load is needed not only for the brain but also for the hands.
The original manual expander from the studio of Artemy Lebedev is pleasantly pleasing to the eye and you want to squeeze it :)

You can also wiggle before the girls talking about the Moebius loop and its number of surfaces after effective work.
Like it or not, but a useful thing.

UPD : Good minus. If this thing is not useful to you, why should I underestimate that karma? Shake your hands better - you'll be healthier!