At caving conventions aboveground, cavers often squirrel themselves through adjustable wooden "squeeze boxes" in good-natured competitions. In the safety of this controlled setting, cavers may push their capacities far beyond what they might hazard underground; […] A very slender woman's tightest squeeze may be defined by the width of her skull turned sideways. Some women thus emerge from squeeze boxes, triumphant, with mirrored abrasions over their cheekbones.