This isn't entirely an invention, so I'm happy for it to be
MFDd, unless it counts as an invented way to amuse onself
I have just noticed a strange and curious effect on the LCD
screen of my MacBook Pro (an old one), and thought it
might interest or puzzle others.
If you press
(firmly but not too hard) on the screen with a
fingertip, and then suddenly remove your fingertip (from
the screen, not from your finger), you get a sort of ripple
effect. This is not the interesting part. The "ripple" is
caused, I presume, by the slight compression and distortion
of the LCD screen.
Now the interesting part. This works best if the screen is
showing white (like the blank space on this page). Press
the screen at two points, an inch or two apart, then
suddenly remove one fingertip. What happens (at least on
my screen) is that a little shadow zips across the screen
from the place you just removed your finger from, to the
other (still pressing) finger.
No idea if it works on other screens. But it amused me.