Dill

Looks like dill.

The code generates a fractal tree using a recursive function. Slight variations in branch angles and lengths give the tree a more natural look. An earlier version of this idea is here.

import numpy as np
import matplotlib.pyplot as plt


def create_branch(start, angle, length, depth, max_depth):
    if depth > max_depth:
        return
    
    end = start + length * np.array([np.cos(angle), np.sin(angle)])
    plt.plot([start[0], end[0]], [start[1], end[1]], color='green', alpha=0.15)
    
    if depth < max_depth:
        num_branches = np.random.randint(1, 4)
        for _ in range(num_branches):
            new_angle = angle + np.random.uniform(-0.5, 0.5)
            new_length = length * np.random.uniform(0.6, 0.9)
            create_branch(end, new_angle, new_length, depth + 1, max_depth)


plt.figure(figsize=(10, 10))
for plot_num in range(16):

    np.random.seed(plot_num)
    plt.subplot(4, 4, plot_num+1)
    num_main_branches = np.random.randint(5, 10)
    for i in range(num_main_branches):
        angle = 0.1 * np.pi * i/num_main_branches + 0.45*np.pi
        length = np.random.uniform(0.1, 0.25)
        create_branch([0, 0], angle, length, 0, max_depth=8)

    plt.gca().set_aspect('equal', adjustable='box')
    plt.axis('off')
plt.show()