11. As shown in the figure, positive integers starting from 1 are arranged in the following form, and a "L" shaped pattern composed of 3 squares (which can be rotated) is used to frame three of these numbers (in the figure, the sum of the three framed numbers is $10+11+18=39$). If the sum of the three numbers framed by such a "L" shape is 2015, then the largest of these three numbers is $\qquad$.
【Analysis】 676
Assume the largest number is $x$;

If the direction of the “ $L$ ” shaped frame is

If the direction of the “ $L$ ” shaped frame is

If the direction of the “ $L$ ” shaped frame is

If the direction of the “ $L$ ” shaped frame is
then $x-8+x-7+x=2015$, in this case $x$ has no solution;

then $x-7+x-6+x=2015$, in this case the solution for $x$ is 676;

then $x-7+x-1+x=2015$, in this case $x$ has no solution;

then $x-8+x-1+x=2015$, in this case $x$ has no solution; In conclusion, the largest number is 676.