Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 18°C. We apply continuously 67°C heat to the field 1x9
What is the temperature (rounded to whole numbers) in the field 4x4 after 40 iterations according to the Gauss-Seidel iteration

Field in the beginning

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

Field after 4 iterations (rounded after 4th iteration)

3	4	5	6	6	6	6	5	4	2
4	7	9	10	10	11	10	9	7	4
5	9	11	13	13	14	13	12	9	5
6	10	13	14	15	15	15	14	10	5
6	10	13	15	16	16	16	15	11	6
6	11	14	16	17	17	17	15	11	6
7	13	16	17	17	17	16	15	11	6
11	20	20	18	17	16	15	13	10	5
19	40	28	19	15	13	12	10	7	3
28	92	34	16	10	7	6	5	4	2

Temperature in field 4x4 after 40 iterations:

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	6	6	5	4	2
4	7	9	10	10	11	10	9	7	4
5	9	11	13	13	14	13	12	9	5
6	10	13	14	15	15	15	14	10	5
6	10	13	15	16	16	16	15	11	6
6	11	14	16	17	17	17	15	11	6
7	13	16	17	17	17	16	15	11	6
11	20	20	18	17	16	15	13	10	5
19	40	28	19	15	13	12	10	7	3
28	92	34	16	10	7	6	5	4	2

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	6	6	5	4	2
4	7	9	10	10	11	10	9	7	4
5	9	11	13	13	14	13	12	9	5
6	10	13	14	15	15	15	14	10	5
6	10	13	15	16	16	16	15	11	6
6	11	14	16	17	17	17	15	11	6
7	13	16	17	17	17	16	15	11	6
11	20	20	18	17	16	15	13	10	5
19	40	28	19	15	13	12	10	7	3
28	92	34	16	10	7	6	5	4	2

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	6	6	5	4	2
4	7	9	10	10	11	10	9	7	4
5	9	11	13	13	14	13	12	9	5
6	10	13	14	15	15	15	14	10	5
6	10	13	15	16	16	16	15	11	6
6	11	14	16	17	17	17	15	11	6
7	13	16	17	17	17	16	15	11	6
11	20	20	18	17	16	15	13	10	5
19	40	28	19	15	13	12	10	7	3
28	92	34	16	10	7	6	5	4	2