Please help me understand figure on subspace similarity in LoRA paper. [D]

I am studying the LoRA paper and have trouble understanding this figure. The function essentially measures how much of the subspace spanned by the top i vectors is contained in the subspace spanned by the top j vectors in the higher rank matrix. Therefore, j can not be lower than i. So when they say the 3rd and 4th figure zoom in on the lower-left triangle of the 2 left-most figures, how are there values for j=1 and i equals 2 to 8? I dont understand what kind of y-axis the 2 right figures are supposed to be using. Thanks in advance!