If its what I am thinking of,(just the way you phrased your question) most, if not all cabins, have hidden Mickey(s) in them. For example, on the Magic and Wonder, the edge of the lights besides the beds, have Mickey shapes, cut into the borders. Theres probably over 50 hidden on each,the Magic and Wonder, and I dont see that changing with the Dream and Fantasy.
Hidden Mickeys, have been around for a long time,origianting in the parks, and it has evolved into a game of sorts for alot of people to find as many as they can. Theres several books(I just bought my son a copy of the book for CC and the Magic class ships) out that list where in each park they have been seen, and you can assign points for difficulty levels. For example. The Mickey icons on the stacks may be worth 1 point since you can see them from literally miles away. The one hidden in the chandeliers in the atriums of the Magic and Wonder might be worth say 3 or 4 points, since you have to look almost right at them to see them.
Try this link. It shows where most hms are in the workd and on the ships. just keep in mind that the number of hms, can change at a moments notice, due to maintanance etc.