Nonentity Wrapped in Enigma

An event suggests some words:
Duck flies down, lands on the pond.
Encountered later, these words

Will suggest something different,
Reimagined memories
Inside of another skull,

But only if that skull holds
Most of these words already,
Plus knowledge of their syntax.

It is a cold pond, in fall,
A sunny but windy day.
The waves look choppy and blue.

No one’s boating or fishing.
No one’s swimming or freezing—
All events that have happened

In this pond’s vicinity,
Different water and weathers,
Similar ducks in the waves.

What’s your memory done now?
What nonentity wrapped in
An enigma have you seen?