import numpy as np

def _mask(r_width, r_hight):
    mask = np.zeros((r_hight, r_width), dtype=int)
    x_mid = int(r_width / 2)
    y_mid = int(r_hight / 2)
    x_step = (r_width-1) / (r_hight-1)

    for y in range(y_mid):
        mask[y][x_mid - int(x_step * y) - 1 : x_mid + int(x_step * y) + 1] = 1
    for y in range(y_mid, r_hight):
         mask[y][x_mid - int(x_step * (r_hight - y)) : x_mid + int(x_step * (r_hight - y)) + 1] = 1
    
    return mask

print(_mask(6,7), _mask(7,7), _mask(8,8), sep="\n\n")