בְּאַרְבַּ֜עַת מִקְצֹע֤וֹת הֶֽחָצֵר֙ חֲצֵר֣וֹת קְטֻר֔וֹת אַרְבָּעִ֣ים אֹ֔רֶךְ וּשְׁלֹשִׁ֖ים רֹ֑חַב מִדָּ֣ה אַחַ֔ת לְאַרְבַּעְתָּ֖ם מְׄהֻׄקְׄצָׄעֽׄוֹׄתׄ׃
In the four corners of the court there were courts inclosed, forty cubits long and thirty broad; these four in the corners were of one measure.
Rashi on Ezekiel
open enclosures We learned in Tractate Middoth (2:5): קְטֻרוֹת means that they had no roofs, and there it is explained what they were used for.