A transparent sheet of acrylic with hundreds of laser-burned holes: that's what the test material looks like. When stretched, it loses stiffness almost linearly: the more holes, the easier it bends. But the rate of this softening is surprising: it's noticeably higher than classical formulas for materials with voids predict.

A camera monitors the surface during stretching and notices that deformation doesn't concentrate in one spot but spreads across the sample, following the hole pattern. Where holes are denser, the material stretches more — stress concentrates near their edges. The strength of samples varies, but the scatter is well described by Weibull statistics — a method that accounts for fracture starting at the weakest point.

Extrapolation shows that stiffness would drop to zero at a porosity much lower than the threshold where holes would be expected to connect into a continuous network. This means the actual geometry of defects matters more than their number. For engineers designing porous parts, from filters to bone implants, this result is a reminder that ideal models can greatly underestimate risk.