A real life Mary's room happened in mathematics in the 1980's when the availability of high speed computers allowed complex fractal structures which had previously been studied entirely through non-visual abstract calculations to be visualized readily and immediately. So, did the most knowledgable experts learn something new? In particular, did the experts on Julia sets suddenly have a "wow" when they saw Julia sets for the first time?To some extent, the answer is yes. The computer calculations revealed some new things. But in regards to this thought experiment, that would be like Mary having incomplete knowledge about red. The more surprising result is to what an extent the answer was no. The computer calculations in their gross features mostly reflected visualizations that were already present in the heads of the experts. When they saw the pictures, they would say, "oh yes, that's about right. That's what I thought it would look like".The greatest impact was on mathematicians that didn't have the visualization in their heads already. One person said that he heard a talk by Julia about these things, but couldn't understand what he was on about until he saw the first pictures. Similar comments can be made regarding simulations of other complex mathematical structures. The Mary's room business is actually a commonplace thing in mathematics.
