Chibanyの謎の弁当

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15

import matplotlib.pyplot as plt

# Create histogram
plt.figure(figsize=(10, 6))
plt.hist(weights, bins=15, edgecolor='black', alpha=0.7, color='steelblue')
plt.axvline(weights.mean(), color='red', linestyle='--', linewidth=2,
            label=f'Average: {weights.mean():.1f}g')
plt.xlabel('Weight (grams)', fontsize=12)
plt.ylabel('Frequency', fontsize=12)
plt.title("Chibany's Mystery Bentos - First Month", fontsize=14, fontweight='bold')
plt.legend(fontsize=11)
plt.grid(axis='y', alpha=0.3)
plt.tight_layout()
plt.savefig('mystery_bentos_histogram.png', dpi=150, bbox_inches='tight')
plt.show()

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.patches import Circle, Polygon

def draw_seesaw_panel(ax, fulcrum_position, title, show_calculation=True):
    """Draw a single seesaw panel with given fulcrum position"""

    # Bento positions and masses
    pos_hamburger = 350
    pos_tonkatsu = 500
    mass_hamburger = 0.3
    mass_tonkatsu = 0.7

    # Calculate distances from fulcrum
    dist_hamburger = abs(pos_hamburger - fulcrum_position)
    dist_tonkatsu = abs(pos_tonkatsu - fulcrum_position)

    # Calculate torques
    torque_left = mass_hamburger * dist_hamburger if pos_hamburger < fulcrum_position else 0
    torque_right = mass_tonkatsu * dist_tonkatsu if pos_tonkatsu > fulcrum_position else 0

    if pos_hamburger > fulcrum_position:
        torque_right += mass_hamburger * dist_hamburger
    if pos_tonkatsu < fulcrum_position:
        torque_left += mass_tonkatsu * dist_tonkatsu

    net_torque = torque_right - torque_left

    # Calculate rotation angle (exaggerated for visibility)
    max_angle = 25  # degrees
    rotation_angle = np.clip(net_torque * max_angle / 50, -max_angle, max_angle)

    # Draw seesaw
    seesaw_length = 200
    seesaw_left = fulcrum_position - seesaw_length / 2
    seesaw_right = fulcrum_position + seesaw_length / 2

    # Apply rotation
    angle_rad = np.radians(rotation_angle)
    left_y = -seesaw_length / 2 * np.sin(angle_rad)
    right_y = seesaw_length / 2 * np.sin(angle_rad)

    # Draw the seesaw plank
    ax.plot([seesaw_left, seesaw_right], [left_y, right_y],
            'k-', linewidth=6, solid_capstyle='round', zorder=2)

    # Draw fulcrum (triangle)
    triangle_size = 15
    triangle = Polygon([
        [fulcrum_position - triangle_size/2, -triangle_size],
        [fulcrum_position + triangle_size/2, -triangle_size],
        [fulcrum_position, 0]
    ], facecolor='red', edgecolor='darkred', linewidth=2, zorder=3)
    ax.add_patch(triangle)

    # Draw bento masses (circles positioned on seesaw)
    # Calculate actual positions on rotated seesaw
    hamburger_offset = pos_hamburger - fulcrum_position
    tonkatsu_offset = pos_tonkatsu - fulcrum_position

    hamburger_y = hamburger_offset * np.sin(angle_rad)
    tonkatsu_y = tonkatsu_offset * np.sin(angle_rad)

    # Hamburger bento
    circle_hamburger = Circle((pos_hamburger, hamburger_y + 8),
                             radius=8, facecolor='orange',
                             edgecolor='darkorange', linewidth=2, zorder=4)
    ax.add_patch(circle_hamburger)
    ax.text(pos_hamburger, hamburger_y + 25, '30%\n(350g)',
           ha='center', va='center', fontsize=10, fontweight='bold')

    # Tonkatsu bento (larger circle to show 70%)
    circle_tonkatsu = Circle((pos_tonkatsu, tonkatsu_y + 8),
                            radius=12, facecolor='brown',
                            edgecolor='saddlebrown', linewidth=2, zorder=4)
    ax.add_patch(circle_tonkatsu)
    ax.text(pos_tonkatsu, tonkatsu_y + 30, '70%\n(500g)',
           ha='center', va='center', fontsize=10, fontweight='bold')

    # Mark fulcrum position
    ax.axvline(fulcrum_position, color='red', linestyle=':', alpha=0.5, zorder=1)
    ax.text(fulcrum_position, -40, f'Fulcrum\n{fulcrum_position}g',
           ha='center', va='top', fontsize=9, color='red', fontweight='bold')

    # Show calculation if requested
    if show_calculation:
        calc_text = f"Left torque: {torque_left:.1f}\nRight torque: {torque_right:.1f}"
        ax.text(0.05, 0.95, calc_text, transform=ax.transAxes,
               fontsize=9, va='top', bbox=dict(boxstyle='round',
               facecolor='wheat', alpha=0.8))

    # Determine balance state
    if abs(rotation_angle) < 1:
        balance_state = "⚖️ BALANCED!"
        balance_color = 'green'
    elif rotation_angle > 0:
        balance_state = "↻ TIPS RIGHT"
        balance_color = 'red'
    else:
        balance_state = "↺ TIPS LEFT"
        balance_color = 'blue'

    # Title with balance state
    ax.text(0.5, 0.98, title, transform=ax.transAxes,
           ha='center', va='top', fontsize=12, fontweight='bold')
    ax.text(0.5, 0.88, balance_state, transform=ax.transAxes,
           ha='center', va='top', fontsize=14, fontweight='bold',
           color=balance_color)

    # Clean up axes
    ax.set_xlim(320, 530)
    ax.set_ylim(-50, 50)
    ax.set_aspect('equal')
    ax.axis('off')

# Create figure with 3 panels
fig, (ax1, ax2, ax3) = plt.subplots(1, 3, figsize=(16, 5))

# Panel 1: Fulcrum too far left (tips right)
draw_seesaw_panel(ax1, 400, "Fulcrum at 400g")

# Panel 2: Fulcrum too far right (tips left)
draw_seesaw_panel(ax2, 480, "Fulcrum at 480g")

# Panel 3: Fulcrum at E[X] (balanced!)
draw_seesaw_panel(ax3, 455, "Fulcrum at E[X] = 455g")

plt.suptitle("Why E[X] is the Balance Point",
            fontsize=16, fontweight='bold', y=1.02)
plt.tight_layout()
plt.savefig('seesaw_balance_point.png', dpi=150, bbox_inches='tight')
plt.show()

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17

import matplotlib.pyplot as plt

# Plot histogram with both averages
plt.figure(figsize=(10, 6))
plt.hist(weights, bins=30, alpha=0.7, edgecolor='black', color='steelblue')
plt.axvline(observed_average, color='red', linestyle='--', linewidth=2,
            label=f'Observed average: {observed_average:.1f}g')
plt.axvline(theoretical_expected, color='blue', linestyle='--', linewidth=2,
            label=f'Theoretical E[X]: {theoretical_expected}g')
plt.xlabel('Weight (g)', fontsize=12)
plt.ylabel('Frequency', fontsize=12)
plt.legend(fontsize=11)
plt.title("1000 Days of Mystery Bentos", fontsize=14, fontweight='bold')
plt.grid(axis='y', alpha=0.3)
plt.tight_layout()
plt.savefig('simulation_validation.png', dpi=150, bbox_inches='tight')
plt.show()