I build the pyramid again and came across this problem here. No matter what I do, I just can’t figure out why this happens.
When I try to create new faces between the selected vertices (F), this happens: The strange thing about it is that it only happens on one side of the pyramid, I could build the other stairs of the pyramid without problems. It also only happens when I select the lowest 2 vertices: Creating a face between them above works fine: I removed all doubles and set the normals outside, however I don’t see my mistake. Is this a bug? Help would be appreciated, this problem really got my interest.
Hard to say by the screens, show your .blender file