https://collection.cooperhewitt.org/objects/68802337/

I think this picture from the cooper hewitt collection shows contrast because of the use of the different colors together in the squares. (green and red, black and red, blue and red, and yellow and red.

https://collection.cooperhewitt.org/objects/1108806857/

I like the use of contrast with the grey and black in this photo. Also, the big and small circles and triangles.

https://collection.cooperhewitt.org/objects/69124515/

The contrast shows in the light green and dark green colors.