Besides the above replies, if the x1 were somewhere else it would be more wordy/awkward (well, not really) to say things like {mi viska lo gusni}.
I've definitely noticed a pattern in the gismu that, when possible, if it makes sense to say "the garden" then most likely the x1 position ( of {purdi} for instance) is going to be "x1 is a garden". So likewise "the light".
This really tripped me up with {rinka}/{mukti}/{krinu}. From my english "x1 causes x2" sounds right, but "x1 does something for reason x2" also sounds right (even though "the reason" is in x2).