# Infect a few random people

to_infect = 10

for i in range( to_infect ):
    cell_available = False
    while not( cell_available ):
        x = random.randint( int( grid_width / 2 ) , grid_width - 1 )
        y = random.randint( int( grid_height / 2 ) , grid_height - 1 )
        cell_available = ( grid[ y ][ x ] == 1 )
    grid[ y ][ x ] = 2