Rhombicus is a fake fair isle beanie completeley knitted in 4-ply sock yarn.
You can also use Acrylic yarn of similar weight or even 5-ply yarn then it will turn out more slouchy.
I used Opal surprise (blue-yellow) and söckli black.
But you can certainly use any sock yarn of any manufacturer you prefer.
As you just need about 35 g in black and 35 g in multicolor it is also a great sock yarn leftover stash buster project!
It has a two-color (corrugated) ribbing and a lovely allover rhombus pattern.
The top is especially lovely because the decreases form a lovely star at the crown.
The standard size fits 52 - 54 cm head circumrefernce. But by adding, leaving out a pattern repeat in width and height the pattern is adjustable to any size!
You could also knit the standard size with 5-ply yarn and bigger needle size to knit it in a bigger size.
Enjoy and happy knitting!
Rhombicus ist eine "Fake"(Falsche) Fair Isle Mütze, die mit 4-fach Sockenwolle gestrickt ist.