[vitaflo]

They're sketches, it's part of the brainstorming process. As stated in the final presentation, Rand was trying to get away from the capital "EXT" in the name from reading like "EXIT". He ended up using a lowercase E for that, but it's obvious from the sketches he started first by stylizing the X instead, basing it on the Bifur typeface (as referenced in the presentation booklet).

Since the logo with the "hourglass" styling was never presented to NeXT, it was obvious that it wasn't considered a strong candidate to show as part of the design process for any number of reasons.

It's important to remember that brainstorming and sketching are just that. You're just trying to get all the ideas out there, you critique them afterwards. We usually do not see those sketches, so I wouldn't take them literally.