What is the main difference between "The Purple Cow" and Frost's poem "Mending Wall"?

the use of rhyming in "The Purple Cow"

the use of rhyming in "Mending Wall"

the use of free verse in "Mending Wall"

the use of iambic pentameter in "The Purple Cow"

A stone wall separates the speaker’s property from his neighbor’s. In spring, the two meet to walk the wall and jointly make repairs. The speaker sees no reason for the wall to be kept-there are no cows to be contained, just apple and pine trees. He does not believe in walls for the sake of walls. The neighbor resorts to an old adage: "Good fences make good neighbors." The speaker remains unconvinced and mischievously presses the neighbor to look beyond the old-fashioned folly of such reasoning. His neighbor will not be swayed. The speaker envisions his neighbor as a holdover from a justifiably outmoded era, a living example of a dark-age mentality. But the neighbor simply repeats the adage.