10. In the example $(\Delta \square)^{\triangle}=\square \bigcirc \square$ the digits are encoded with geometric shapes. (Identical digits correspond to identical shapes, different ones to different shapes.) Decode these digits.
10. From the condition, it is clear that raising a two-digit number to a power results in a three-digit number. Considering that even $10^{3}=1000$, the exponent can only be 2, i.e., $\Delta=2$. Since the base of the power ends with the same digit as the power, $\square$ can be $0,1,5$ or 6. The condition is only satisfied by $\square=6$. As a result, we have $26^{2}=676$.