וְלַכָּתֵ֣ף הַשֵּׁנִ֗ית מִזֶּ֤ה וּמִזֶּה֙ לְשַׁ֣עַר הֶֽחָצֵ֔ר קְלָעִ֕ים חֲמֵ֥שׁ עֶשְׂרֵ֖ה אַמָּ֑ה עַמֻּדֵיהֶ֣ם שְׁלֹשָׁ֔ה וְאַדְנֵיהֶ֖ם שְׁלֹשָֽׁה׃
And so for the other side; on this hand and that hand by the gate of the court were hangings of fifteen cubits; their pillars three, and their sockets three.
Read kabbalistic (mystical) interpretation of Exodus 38:15: and classical mystical sources.