I felt the the first two blasts even though I work a couple of blocks away. It was kind of odd because we were facing away from the blast, and the people on the streets didn't seemed alarmed so we were all speculating on what caused it. It wasn't until I went upstairs to where we had the entire floor open that I realized in which direction the explosion occurred. The smoke had cleared by that time but one of my coworkers had a picture of the cloud of smoke immediately after the explosion. Later in the day we heard another explosion but the building didn't shake like it did during the first two.