Denise Levertov's poem, "A Time Past" uses visual imagery to conjure up moments from the past.

The first bit of visual imagery is found in the mention of the steps:

The old wooden steps to the front door...

These words conjure an image of wooden steps that are never quite clean, even when swept, but are worn soft by age and use, though they are still capable in the speaker's memory to leave slivers behind.

Another visual image presents a beautiful morning, awash in sunlight, early and cold enough that the dew is almost frost.

...(emerging into golden day— the dew almost frost)...

Another visual image is the description of the old steps now; there may be foreshadowing in this statement that the steps are gone, dead:

...those wooden steps are gone now, decayed...

And the description of the new steps conveys not only that the old has been replaced, but replaced by strong, cold steps—as if they have beauty, but no soul:

...replaced with granite, / hard, gray, and handsome...

The woman refers once more to that enchanted moment when "he" came downstairs, the memories of his youth, his return of her exclamation of love ringing out in the silence:

Yet that one instant, / your cheerful, unafraid, youthful, 'I love you too,' / the quiet broken by no bird, no cricket, gold leaves / spinning in silence down without / any breeze to blow them.

The memory of that moment wraps around the speaker, "twining" itself like a clinging vine, attaching itself in her mind to those old steps, permanently a part of that moment; however the moment is gone, and perhaps the visual imagery that ends the poem parallels the deterioration of the relationship as well as the steps:

Yet that one instant...is what twines itself / in my head and body across those slabs of wood / that were warm, ancient, and now / wait somewhere to be burnt.