I'm pretty sure "a red square" was sgwâr coch before, so I thought sgwâr was masculine. But here bach is mutated. So sgwâr can be either masculine or feminine?
No, it's masculine. Sgwâr bach is the correct answer and is in the course. This mistake was deleted by us some time ago but still lingers because of the Duolingo system error.
Ok, I'll ignore it then. Thanks.
rmcode is incorrect; sgwâr is both masculine and feminine: http://geiriadur.ac.uk/gpc/gpc.html?sgw%C3%A2r Depending on the speaker and the region, it could be sgwâr fach or sgwâr bach.