ReBoot

Concerning back-up and phong. There icon's are similar, Both have the triangles in them and now you mentions it, they are both sort of similar in design. Not fleshy like normal sprites. There icons could be different because there coding is different to a regular sprites?
This next bit goes abit off topic, but, Matrix says to Back-up, that he didnt think there were any sprites left. Now, i've always wondered why there werent as many sprites and binomes, and i read somewhere, that welman matrix lead them all to battle and they died? (this was written before season 4)
I think the normal icon is black and white to show that the person bareing it is basic and normal, where as with the guardian one's, being yellow and black, shows that the barer has some form of upgrade, as being the same with the viral ones, showing that there code is slightly changed.
I notice the "guardian binome" too, perhaps he is an under cover guardian, from the super computer, looking after bob?
Hope i helped! (:

The number of sprites vary from system to system - I read somewhere that Mainframe's twin city actually had an unusual surplus of sprites, and that most died (or I suppose became nullified) during the explosion that created Lost Angles.
As for Phong, he started out as Command.com, and then he seems to have just retained his status as a ReadMe archiver, a repository of wisdom.
With Backup, perhaps it's just a symptom of being a sprite from a different system. Who is to say that sprite icons in different systems aren't slightly different? Maybe that system is using Linux or something. ;)

DraloreShimare: I thought about that too, but all the other guardians all have the same icon as Bob. I was looking to see if there was a Phong-like or Backup-like icon in Guardian colors on a Guardian somewhere, but it doesn't seem to be the case.

I'm sure it wasn't just a random design choice. I feel like there's a reason that isn't apparent in the details of the show that the designers and writers had.

We might never know :o

Back-Up's icon is different because he is from a different system. No one said all icons were the same.

Phong's icon is different because he is the keeper or the core.

The British Binome still boggles my mind.

Everyone else from Back-up's system had a normal reboot icon. So did everyone from every other system they visited (save for the Search Engines like Ray).

Ray Tracer's icon is the Motorola icon with the letter M. I think it's because he's a second generation web surfer/ search engine.

As for Phong, there are other people that have a similar design to him. The search engine Maxine from "The Episode with No Name" has a metallic look, as well as Back-Up. Also, Hack and Slash have a metallic look. Neither Phong nor Hack/Slash have legs. Instead they move around with a ball.

In regards to Phong's icon, it could be because he is part DOS and part windows / linux. This website explains it better: http://reboot.wikia.com/wiki/Icon

okay so the normal icons are the black and white with the white and black triangles...the guardian icons i always thought were a gold colour rather than yellow so i figured that since they were "guardians" and therefore special (bob wasn't effected by hex's medusa virus implying his code was different) they merited this gold colour on their icon...the viral color added to the icon shows which virus has effected what PID (enzo's icon turned red and black when hex gave him a little part of her code)(megabyte's viral binomes had green and black) so to me the black represents a basic code present and the white shows a potential to add more code...
as for the different shapes y'all bring up a very good point that Back-Up's icon is different from the other inhabitants of his system so I can only assume that he's like an upgraded version of phong kind of like how computer programs see upgrades and look different and are better...the reason this is my conjecture is because they are the

metallic gold colour and based on Back Up's head structure (looking like a huge brain) makes me assume that his function would be similar...i'm actually watching that episode now and i may change my mind lol but the black and white ones with the alternating triangles seem to be universal i think i'm changing my mind right now and i think maybe the writers were trying to emphasize that the systems to which matrix and andraia were traveling were far different from their own

hmmm... andraia's is different because she's a game sprite so naturally their icons would be different and as for the british binome? he confuses me too lol i think i like the idea of him being a guardian from the super computer although his motives are ambiguous...is he watching over bob? or maybe pearson (despite quitting the guild he still may know some code))

I still like the icon from the evil dead game they played, It's black with a little skull in it...night of the living binomes o_O...ooooOOOOOOooooOOOOO, XD!!!!