Moving Ladder Constant

N.B. A detailed on-line essay by S. Finch was the starting point for this entry.

What is the longest ladder which can be moved around a right-angled hallway of unit width? For a straight, rigid ladder, the answer is $2\sqrt{2}$. For a smoothly-shaped ladder, the largest diameter is $\geq 2(1+\sqrt{2}\,)$ (Finch).

See also Moving Sofa Constant, Piano Mover's Problem

References

Finch, S. ``Favorite Mathematical Constants.'' http://www.mathsoft.com/asolve/constant/sofa/sofa.html