def initialise():
    global processing
    processing = True
    for col in range(COLS):
        for row in range(ROWS):
            grid[(col, row)] = EMPTY
    grid[(initial_cell_col, initial_cell_row)] = INITIAL
    grid[(terminal_cell_col, terminal_cell_row)] = TERMINAL
    processing = False
def initialise():
    global processing
    processing = True
    for col in range(COLS):
        for row in range(ROWS):
            grid[(col, row)] = EMPTY
    grid[(initial_cell_col, initial_cell_row)] = INITIAL
    grid[(terminal_cell_col, terminal_cell_row)] = TERMINAL
    processing = False