Yeah, me neither. Until I opened the box, stared at the triangle for a few minutes and finally my brain started working

 you could buy one? 2600EUR for the stock build kit (not bad at all, but I like my rides custom)
or try to find a testbike?

I'm sure in Poland fatbikes are more common than here in Belgium

 No, not in production. Some guys made a Santa Cruz V10 with fat wheels though It was funny to see! I'll post the pic if i find it.

 to avoid rub between the chain and the 4.7" tyre, the rear wheel must be built with an offset.

 its actually to have a proper chain line.

 Thats what he said.

 A good chainline and tyre/chain rub are 2 different things. Even with the 28mm rear hub offset, the chainline isn't optimal when using a 100mm wide double chainring crankset and a 9/10sp cassette. I'm running only one ring and an Alfine hub, so I'm not worrying about that.

 I agree. Although a good chainline wont rub on a tire.