The answer is allusion.
Allusion is mentioning something briefly, not really going into the details of it.
Winter and summer cause they are easy to write and think about
The Holy Sonnets—also known as the Divine Meditations or Divine Sonnets—are a series of nineteen poems by the English poet John Donne (1572–1631). The sonnets were first published in 1633—two years after Donne's death.
It might be saying that not everything fun has to be dangerous.
