In the letter of Az-Zumar (39) verse 5, Allah says:
"He created the heavens and the earth with haq: He closed the night (yukawwiru) over the day and closed (yukawwiru) noon over night ..."
An overview of day and night cover each other when viewed from a certain place on earth. This is how Allah shut the "yukawwiru" night into the afternoon and vice versa.

The "closing" (yukawwiru) in the above verse in Arabic has the notion of "coating something with a circular thing", usually used in terms of "wrapping a turban on the head." The origin of the word is "kurah" (كرة) which means ball or round object (such as head). So again implicitly God wants to tell man that the shape of the earth is round.