Here you can see a detail of one of the walls in the Ben Youseff Madrasa. I do not know Arabic, but I think part of the decorations in the above panel are letters in Arabic. In the panel bellow you can see representations of flowers. Remember that in the Islamic countries, it is forbidden to use representations of human beings.
If you plan a visit to Marrakech, you have to know that most of the visits can be done on foot. You will need to take a local taxi ("Petit Taxi " for a maximum of three passengers, and the "Grand Taxi " for up to six passengers) to get to the medina from your hotel -- in case you stay in the new Marrakech. If you stay in a hotel in the medina, you will not have to take any public transport. Be advised that you will have to walk a lot. Distances are not that big, but most probably you will get lost and will walk the same part of the medina several times in order to find what you are looking for.