The "sprung rhythm" that Hopkins uses in this poem emphasizes the stressed first syllables in each line. The stresses are on the variety of things (images) that the speaker sees in the world. This poem is a praise of God's brilliance in creating difference, change, and variety in the world. The images are stressed to highlight their variety (stressed syllables in bold): 

For skies of coupled-colour as a brinded cow; 

For rose-moles all in stipple upon trout that swim; 

Fresh-firecoal chestnut-falls; finches' wings; 

Hopkins also uses alliteration to add more stress to the images and connects them, albeit with a start and stop sound: "With swift, slow; sweet, sour; adazzle, dim;" This start and stop sound or rhythm highlights the difference and variety as if he is saying, "There's this and that and that and that." Hopkins celebrates these differences and the change in life by recognizing the variegated patterns that represent change, (a pattern being a differentiated interruption of one united color): "freckled," "dappled," and "pied."  Hopkins praises God, a perfectly unchanging being, to create such change and variety in life.