Anthony wondered why Humayun's tomb had jewish symbols on it.
I looked into this out of curiousity. The symbol in question was the six pointed star, known in geometry as a hexagram.
The answer is simple: the hexagram is not an exclusively jewish symbol, but also common to the other semitic religions as well as eastern ones. In the context of Islam specifically, the origin may be in the ring of King (and prophet too, so don't draw any cartoons) Solomon/Sulayman. This ring had great powers (LOTR?!) and was in the shape of a hexagram. The history of Sulayman may be open to debate, but it seems clear that the hexagram was used among other geomtrical patterns for decoration in muslim societies (for eg on coins and on pottery). So have either of you seen the hexagram in other Islamic architecture?