The first is easy
Then you have to get creative.
(
xihpete A neutrino walks straight through a bar, with v>c.,
Tue 16 Feb 2010, 1:13,
archived)
A guillotine whose blade is tied to one arm
So that when that arm is removed, the blade falls onto the other, removing that one.
(
xihpete A neutrino walks straight through a bar, with v>c.,
Tue 16 Feb 2010, 1:22,
archived)