• $$\frac{c_1}{c_1+d_1}$$ on the lower left
• $$\frac{c_2}{c_2+d_2}$$ on the lower right
• $$\frac{a_1}{a_1+b_1}$$ on the upper left
• $$\frac{a_2}{a_2+b_2}$$ on the upper right