Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 20°C. We apply continuously 66°C heat to the field 2x6
What is the temperature (rounded to whole numbers) in the field 8x9 after 136 iterations according to the Gauss-Seidel iteration

Field in the beginning

20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020
20202020202020202020

Field after 4 iterations (rounded after 4th iteration)

3566777652
5810111212121084
610131415151513105
612171818181715116
818272623211917126
1331524030242118137
18491185836262218137
1433544230242016116
91928252118151284
4912121198642

Temperature in field 8x9 after 136 iterations: