straight line is the shortest path between two virtual points.
Context can play a key role in interpreting a line. Müller-Lyer's
illusion, due to German sociologist Franz Carl Müller-Lyer
(1857-1916), proves that a segment can visually appear longer
or shorter if it is framed between two angle brackets the points
of which are directed either outwardly or inwardly, as illustrated
in fig. 1 below.
happens if we do add motion to the illusion? As shown on the
animated gif, the central red dot is equidistant from the other
two red dots, although the ends of the line visually appear
to alternately stretch and shrink like a rubber band!
the sequence of the 26 basic frames of the animated gif, it
would also be possible to create an amusing flipbook!
Below an hypnotic radial pulsating variant. Though the star seems
to pulsate the blue and black segments are always the same length.
enough, the illusion seems to work even though the two segments
that form the line aren’t straight, as shown in the animation
lot of compelling and artistic variants can be created with
my dynamic concept! The vertical color segments of the pattern
below are always the same length. In this version comes into
play the "neon
color spreading" effect...
geometric illusions involve V-shaped lines… You can see
similar effects in fabric patterns (Zöllner
illusion), in the moon
illusion (the moon appears larger in the horizon due to Ponzo
illusion effect), in the distribution of a line in a closed
parallelogram), etc. A similar illusory effect applies
also to time perception: time that is filled with activities
(compacted line with arrow heads pointing outside) seems shorter
than empty time, when we have nothing to do (unwrapped line
with arrow heads pointing inside).
did I discover this dynamic illusion?
I hold many optical illusion workshops around Europe. About
two years ago, I presented the Müller-Lyer illusion to
children, using a hands-on exhibit of my creation. The exhibit
consisted of a simple metal board onto which was painted a
line with three red dots: one dot in the middle of the line,
and the two other dots at its ends. A sort of clock hand could
be pivoted at each dot, to empirically experiment the illusory
increasing or decreasing of the segments. To my great surprise,
some children played nonstop with the thin revolving hands
of the exhibit, mesmerized by the illusory effect. That experience
prompted me to create an animated version of the Müller-Lyer