A beautiful series indeed! And rather poignant as well. They seem to tell the tale of fleeting dreams.
They remind me of the first verses of Ecclesiastes for those familiar with this.
for those who are not: Vanity of vanities, says the Preacher,
vanity of vanities! All is vanity.
What does man gain by all the toil
at which he toils under the sun?
A generation goes, and a generation comes,
but the earth remains forever.
(Having just reread the opening lines, it struck me how relevant they still are)
And for those that feel these are gloomy lines, the conclusion was that we'd still better be pushing on.
Also rather relevant to our times