וּמַ֨רְאֵיהֶ֔ם דְּמ֥וּת אֶחָ֖ד לְאַרְבַּעְתָּ֑ם כַּאֲשֶׁ֛ר יִהְיֶ֥ה הָאוֹפַ֖ן בְּת֥וֹךְ הָאוֹפָֽן׃
And as for their appearance, they four had one likeness, as if a wheel had been within a wheel.
Read halakhic rulings (Jewish law) on Ezekiel 10:10: and classical halakhic sources.