There are in fact two sided floppies! IIRC they behave a lot like the two sides of a cassette tape, the floppy reader only reads from one side at a time.

A fun fact in that regard: the game Karateka (an actual game for the Apple II) had an easter egg, where the team realized that their game entirely fit in the capacity of one side of a floppy, so they put a second copy of the game on the other side, but set up so that it would render upside-down.

I'd not be surprised if the inclusion of that detail in this post was directly inspired by Karateka.

The Apple II had a non-linear layout of video memory, so programmer Jordan Mechner used a layer of indirection where he had an array of pointers to rows of screen memory.

They realized that inverting the screen was as simple as inverting the row-pointer array. Then they managed to convince Broderbund to ship a double-sided floppy with that change in the software.