Your "this bluey greeny triangle/pixel looking pattern" appears to be the Caltex logo but sampled with the greeny bits as the dark and the other colour being a contrast/brightness thing.
Colors > Colorise - map your thing to a colour. Have a fiddle.
I exported the whole thing as a JPG and then cut and pasted the roundel using a transparent selection in Paint.
I'f be inclined to take your repeat pattern an used it underneath some transparent players in your photobox/shop program of choice.
I can not tell you how to get there, but the road is somewhere over there I think.