I was considering starting to watch the Nichijou anime series, and then thought that maybe I should read the manga first. Then I noticed that MAL lists Helvetica Standard as Nichijou's manga side-story, and that there is also an OVA listed as a prequel to the anime series, and 14 1-minute special episodes listed as the anime's side-story.
Bearing all this in mind, I thought I might as well ask:
Is the anime (including the OVA and specials) a faithful adaptation of the manga (including the side-story), with only slight variations? Or does it add a lot of new content, and possibly stray from the original content?
Or should they be regarded as two separate pieces?