In many ancient brick structures, the mortar is stronger than the brick -- at least at the time of collapse. The mortar retains its shape, and the bricks have collapsed & turned to dust. At 11:57 PM 12/26/2014, Bill Gosper wrote:

Who needs mortar? gosper.org/martinsmarbles.png --rwg

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QUESTION: Using L:1 rectangular bricks, does there exist any pattern such that the crack length amplification factor always is >=C, for some C>sqrt(2), no matter what direction? What is the greatest achievable C?

If nonconvex tesselators are allowed, then Gosper's fractal "snowflake" shaped "bricks" would assure crack-length amplification factor of INFINITY... but only in the limit where the mortar thickness tends to 0.