In 1955 William Carlos Williams published Journey to Love, and in The Ivy Crown Williams uses a sort of stream of consciousness that is similar in length and structure to Perpetuum Mobile. In the first stanza of The Ivy Crown, Williams makes a reference to the story of Antony and Cleopatra, which is interesting to compare with To Mark Antony in Heaven, which was published in 1913, in order to more clearly see the differences between his early and later works:

Antony and Cleopatra/were right;/they have the shown the way. I love you/or I do not live

Why did you follow/that beloved body/with your ships at Actium?/I hope it was because/you knew her inch by inch/from slanting feet upward/to the roots of her hair

To Mark Antony in Heaven

In the earlier poem, the speaker is addressing Antony, and he is making the statement that love is more important than honor. Then, 45 years later, Williams applies the story of Antony and Cleopatra to his personal life, and both the tone and language seem much more personal and meaningful, especially by using I and you, as opposed to simply making a general statement which applies to all. In addition, there is the concept of mature, experienced love versus that of young lovers:

love is cruel/and selfish/and totally obtuse-/at least, blinded by the light,/young love is./But we are older

This demonstrates a strong connection to the metaphor of Antony and Cleopatra's relationship. While To Mark Antony in Heaven made a powerful statement about love, it was a slightly more superficial reaction, at least in comparison with the greater depth of analysis shown in The Ivy Crown.

The whole process is a lie,
        unless,
            crowned by excess,
It break forcefully,
        one way or another,
            from its confinement-
or find a deeper well.
        Antony and Cleopatra
            were right;
they have shown
        the way. I love you
            or I do not live
at all.

Daffodil time
         is past. This is
              summer, summer!
the heart says,
         and not even the full of it.
              No doubts
are permitted-
         though they will come
              and may
before our time
         overwhelm us.
              We are only mortal
but being mortal
         can defy our fate.
              We may
by an outside chance
         even win! We do not
              look to see
jonquils and violets
         come again
              but there are,
still,
         the roses!

Romance has no part in it.
         The business of love is
              cruelty which,
by our wills,
         we transform
              to live together.
It has its seasons,
         for and against,
              whatever the heart
fumbles in the dark
         to assert
              toward the end of May.
Just as the nature of briars
         is to tear flesh,
              I have proceeded
through them.
         Keep
              the briars out,
they say.
         You cannot live
              and keep free of
briars.

Children pick flowers.
         Let them.
              Though having them
in hand
         they have no further use for them
              but leave them crumpled
at the curb's edge.

At our age the imagination
         across the sorry facts
              lifts us
to make roses
         stand before thorns.
              Sure
love is cruel
         and selfish
              and totally obtuse-
at least, blinded by the light,
         young love is.
              But we are older,
I to love
         and you to be loved,
              we have,
no matter how,
         by our wills survived
              to keep
the jeweled prize
         always
              at our finger tips.
We will it so
         and so it is
              past all accident.