allocate a pair of two dimentional arrays 'newtemp' and 'oldtemp'
set every value of oldtemp to 70 degrees
while (1)
{
          clear the screen // system("cls")
          print oldtemp array
          set the outer edges of oldtemp to 70 degress
          set location (size-2, size-2) of oldtemp to 1000 degrees
          set location (0, size *0.2) through (0, size * 0.5) of oldtemp to 0 degrees
          for every row
                      for every column
                               set newtemp[row][column] to the average of it's oldtemp neighbors
          copy newtemp into oldtemp
   }