An equation or system of equations is said to be "ill-conditioned" if a small change in input data can produce a very large change in the output. This inverse relationship between input and output has become popularly known by the phrase "butterfly effect." Two poets from Eastern Pennsylvania, Gary Fincke and Harry Humes, have written poems about this phenomenon.
The Butterfly Effect by Gary Fincke
If a butterfly flaps its wings in Brazil,
it might produce a tornado in Texas.
from The Law of Chaos
Early in the newsmagazine
these Haitian women are wailing,
and those that are not are holding
their breath and the hands of men
tense with a bullet expectation.
And I've read, too, that the wind
tonight may have originated
from their mourning, the beating
of their arms in the air sending
the record warm front north.
I've read about fractals,
the Russian Dolls of the universe,
diamonds made of diamonds made
of diamonds diminishing in size;
I've learned the Butterfly Effect,
how chaos is not chaos,
how some slaughter in Haiti flaps
its wings and churns into my grip
on the arm of my son, my clenched teeth
and hiss as he flutters his free arm
and wails and changes the future
of weather in a country east of us
where a father will choose, he thinks,
to stun his son to obedience.
And when I leave him to let the dog
walk me into sense, the unnatural wind
chatters the branches that skitter her
to a barking panic on our street
of sculpted shrubbery where Chirstmas bulbs,
in one yard, might be arranged
into language if you're properly
angled, upstairs, across the street,
positioned like an antenna straining
for a distant station, my son in his window
watching me handle the dog, my breath
without its winter clouds, nothing he'd believe
could join the southern grief of a warm front.
Fincke's poem (above) comes from Inventing Angels (Zoland Books, 1994). Humes' poem (below) is found in Butterfly Effect (Milkweed Editions, 1998).
Butterfly Effect by Harry Humes
Think of it in Beijing,
the swallowtail on its white blossom.
Over there a man sleeps
beneath a bo tree.
A woman walks by a pond of red carp.
It is the last of September,
and the sky is clear all the way to the mountains.
No one sees the butterfly's wings move
nor feels the air stir
in the afternoon,
the small disturbance on the pond.
And when the swallowtail flies off
it is just a little more of the same,
a branch creaking, a ripple
over some geography like light over wheat,
except a month later,
thousands of miles away,
a wind knocks trees over,
it snows for days.
Children no longer turn somersaults.
women turn away from sifting and measuring,
a man watches a deer stagger,
starving, across the frozen river.
The horizon hardly stirs,
and all the pianos are silent.
The bright wing of the sky
drifts so close you could raise a hand
to it, the air delicate
and your fingers itching a little,
as if something had landed there.