Staying up until 3am does have its upsides. I stumbled upon an excellent NOVA episode in the wee hours of Sunday morning called "Building on Ground Zero". The program went through both the ASCE and NIST investigations into the collapse of the Twin Towers (WTC1 and WTC2). Both reports came to similar conclusions (impact and explosion of airplane coupled with weakening of steel trusses by fire brought the Twin Towers down), but attributed different mechanisms (pancake floor collapse as opposed to truss connection pulling columns inward causing fracture).
"Building on Ground Zero also focused on a design feature used frequently by structural engineers called redundancy. In structural engineering, redundancy generally means multiple load paths. The ultimate goal of a structural engineer is to safely transmit the loads to the ground. This is usually done by focusing on a primary load path. But what happens when the primary load path is compromised? If the load cannot safely get to the ground, then the equilibrium of the structure is shot and collapse (in part or in whole) occurs. If a structure is said to be redundant, then there are multiple loads paths. Redundancy is also a means to prevent progressive collapse where the failure of a single member causes the failure or collapse of the structure (in part or as a whole). In part, it was the redundancy of Twin Towers' structural design that allowed them to remain standing despite multiple columns being severed, thus allowing several hundred occupants the ability to escape.
So can redundancy in a natural object point towards design? Possibly. Taking the Mike Gene approach, let's grant that a redundant feature in a natural object is possibly the outcome of a purposeful design. In order to progress to plausibility, I propose one of the things that needs to be looked at is the context of the redundancy (i.e. does the redundancy serve a purpose?). Redundancy without meaning or context points more towards a "Myopic Tinkerer" than a "Rational Engineer".
However, there is an interesting flip side to this: I don't believe the designer of WTC1 and 2 intentionally incorporated redundancy for the events of 9/11.* This would mean that redundancy was an accidental outcome rather than purposely used for the case that several columns at a certain point would be missing. So where does this fit in to the "design paradigm" and it is possible to even know if the redundancy was purposely designed or not?
The asylum is now open. Let the comments commence!
*The tubular structure of WTC1 and 2 were designed to resist wind and earthquake loads, as well as the impact of a Boeing 707. I don't believe that the impact studies looked at the possibility that the 707 would take out several columns at a certain elevation, but I could be wrong.