ðeɪ wɜːɹ ɪnvˈɛntᵻd baɪ sˈɛt θˈiəɹɪst dʒˈæk sˈɪlvɚɹ æz ɐ mˈiːnz ʌv pɹˈuːvɪŋ ɡlˈoʊbəl skwˈɛɹ hˈoʊldz ɪnðə kənstɹˈʌktᵻbəl jˈuːnɪvˌɜːs.
They were invented by set theorist Jack Silver as a means of proving global square holds in the constructible universe.