▁ ▁Early ▁Winter s ▁was ▁the ▁first ▁company ▁to ▁realize ▁the ▁significance ▁of ▁G ore - Tex ▁fab rics ▁for ▁out door ▁applications . ▁ ▁In ▁fact , ▁the ▁timing ▁of ▁T anner ' s ▁visit ▁was ▁fort uit ous ▁since ▁Early ▁Winter s ▁had ▁a ▁light weight , ▁single - w alled ▁tent ▁design ▁for ▁which ▁they ▁were ▁seeking ▁a ▁water proof ▁and ▁breath able ▁fabric ▁solution . ▁ ▁When ▁T anner ▁showed ▁Early ▁Winter s ▁the ▁product ▁sample , ▁the ▁Early ▁Winter s ▁staff ▁tried ▁it ▁out ▁by ▁using ▁a ▁rub ber ▁band ▁to ▁secure ▁a ▁sample ▁of ▁the ▁fabric ▁over ▁a ▁coffee ▁cup ▁filled ▁with ▁bo iling ▁water . ▁ ▁This ▁allowed ▁visible ▁steam ▁to ▁pass ▁through ▁the ▁G ore - Tex ▁fabric , ▁but ▁when ▁the ▁cup ▁was ▁turned ▁over , ▁no ▁liquid ▁was ▁claimed ▁to ▁come ▁through . ▁This ▁consumer ▁demonstr ation ▁became ▁known ▁at ▁W . L . ▁G ore ▁& ▁Associ ates ▁as ▁the ▁" Z ▁Square " ▁test , ▁named ▁after ▁Z imm erman . ▁ ▁This ▁" co ff ee ▁cup " ▁demonstr ation ▁has ▁become ▁well ▁known ▁in ▁the ▁out door ▁industry ▁because ▁it ▁is ▁an ▁effective ▁way ▁to ▁convey ▁the ▁concept ▁of ▁fabric ▁that ▁is ▁water proof , ▁yet ▁breath able . ▁ ▁After ▁learning ▁about ▁the ▁product , ▁Nicol ai , ▁Edwards , ▁and ▁Z imm erman ▁requested ▁sample ▁material ▁for ▁experiment ation , ▁and ▁in ▁Winter ▁ 1 9 7 5 , ▁they ▁produced ▁a ▁prototype ▁tent ▁that ▁they ▁subject