Urban Bees Research - can you help?

[Thymallus]

My mistake it was a von Frisch experiment, where he had foragers fly around a building in a dog leg to find a food source, but the dances directed the recruits in a direct line to the food source over the buildings. There is nice diagram of the experiment at this link. Just scroll down until you find it.

[fatshark]

I think that's a slightly different interpretation to mine of the experiment.
The foragers found the food by flying around the building, returned (route unspecified), danced and directed the subsequent bees to use the straight line over the building. They fly in a straight line because the building isn't really an obstacle.
That one I can understand ... I remain perplexed by the one when they can't fly over the obstacle.

[Thymallus]

Perhaps I didn't phrase it very well but that was my interpretation also. I presumed the foragers flew back in a straight line over the building and that the searching pattern round the building was just their easier way of going on the hunt for nectar.
I've been looking for the mountain experiment but haven't found it so far.