Derasha 45 on Terumah 26:1
Source: Yoma 72b
תַּנִּי מִשְּׁמֵיהּ דְּרַבִּי נְחֶמְיָה: מַהוּ מַעֲשֵׂה חֹשֵׁב — מַעֲשֵׂה אוֹרֵג, לְפִיכָךְ שְׁנֵי פַרְצוּפִין.
English: Rabbi Nechemyah explains “ma'aseh choshev” as woven work; therefore it has two faces.