Finding pi in the alphabet

Write the letters of the alphabet around a circle, then strike out the letters that are symmetrical about a vertical line. The remaining letters are grouped in clumps of 3, 1, 4, 1, and 6 letters.

I’ve heard that this observation is due to Martin Gardner, but I don’t have a specific reference.

In case you’re interested, here’s the Python script I wrote to make the image above.

    from numpy import *    import matplotlib.pyplot as plt        for i in range(26):        letter = chr(ord('A') + i)        if letter in "AHIMOTUVWXY":            latex = r"$\equiv\!\!\!\!\!" + letter + "$"        else:            latex = f"${letter}$"        theta = pi/2 - 2*pi*i/26        pt = (0.5*cos(theta), 0.5*sin(theta))        plt.plot(pt[0], pt[1], ' ')        plt.annotate(latex, pt, fontsize="xx-large")    plt.axis("off")    plt.gca().set_aspect("equal")    plt.savefig("alphabet_pi.png")

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