It may be the case that the two pieces of plastic are "yellow back and border" and "grey front cover, " but having any other color on the back invalidates the i

It may be the case that the two pieces of plastic are "yellow back and border" and "grey front cover, " but having any other color on the back invalidates the infringement claim. If they had done a yellow border with grey sides and back, they would not have infringed. If they had done yellow back and grey front (with no border) they wouldn't have infringed. If the had done yellow front and grey back without border or yellow front and back with grey border they wouldn't have infringed. There are all sorts of ways to make a yellow and grey multimeter that don't infringe on Fluke's trade dress. Fluke isn't monopolizing a general two-tone color scheme: They are monopolizing a specific arrangement of two colors, and that is an eminently reasonable thing to do. This is a little like arguing "Well, copyright shouldn't exist because you shouldn't get a monopoly on just some general words." But that's a strawman--you can only obtain a copyright on a specific arrangement of general words.