The tall building is called the Green building (picture has a Calder sculpture in front). Rumour has it that I.M.Pei wanted the building to be seen from Boston, across the Charles River, and in order to make the building higher, he put the building on ‘stiles’, as he was restricted to a certain number of storeys, but the stiles didn’t count and he could win a few meters that way.
MIT students as a ‘hack’, programmed lights in the building to play a tetris game! Check out the video: http://www.youtube.com/watch?v=OnCNGNv-Fds
The Triangular building (The Landau Building) has a textured off-shutter concrete finish externally as well as on the interior walls. The plan of the building is said to be a 30/60 degree triangle.
Interior photos of the Landau building: