physical toys:


Levitating pyrolytic graphite over four neodymium magnets (quadrupole)



Nice beta type Stirling engine running with the heat of your hand



Looks like a normal gyro - but....



it's unstable - precession becomes "stronger"



and at the end it flips. As every cryo it conserves the angular momentum => in the "flipped" position it a the same spin direction as in the first picture :-)