This shows unity through proximity by placing the husband and wife close together. It also shows it through the man holding the pitchfork.

This shows unity by repetition through the use of the same colors in the sky and continually through the man and the bridge.

This shows unity by continuation. This is shown through direction of the swirls in the sky and the continuation of the hills straight into the sky.

This shows unity with variety. This is due to the same woman many times but with different colors in the face and hair.

This shows intellectual unity. This is due to the many watches just scattered throughout the entire painting with no rhyme or reason.