Script to create an Ico Sphere in Blender.

icosphere.py

import bpy


def icosphere(recursion_leve=0):

    # create 12 vertices of a icosahedron
    t = (1 + 5**0.5)/2
    verts = [
        [-1, t, 0], [1, t, 0], [-1, -t, 0], [1, -t, 0],
        [0, -1, t], [0, 1, t], [0, -1, -t], [0, 1, -t],
        [t, 0, -1], [t, 0, 1], [-t, 0, -1], [-t, 0, 1]
    ]

    # create 20 triangles of the icosahedron
    faces = [
        [0, 1, 7],  [0, 5, 1],  [0, 7, 10], [0, 10, 11],
        [0, 11, 5], [1, 5, 9],  [2, 4, 11], [3, 2, 6],
        [3, 4, 2],  [3, 6, 8],  [3, 8, 9],  [3, 9, 4],
        [4, 9, 5],  [5, 11, 4], [6, 2, 10], [7, 1, 8],
        [8, 6, 7],  [9, 8, 1],  [10, 7, 6], [11, 10, 2]
    ]

    # midpoint vertices cache to avoid duplicating shared vertices
    mid_cache = {}

    def get_mid_point(a, b):
        '''return index of vertex in the middle of a and b'''

        key = (a+b)*(a+b+1)//2 + min(a, b)  # Cantor's pairing function
        if(key in mid_cache):
            return mid_cache.pop(key)
        v_a = verts[a]
        v_b = verts[b]
        mid = [(v_a[0]+v_b[0])/2, (v_a[1]+v_b[1])/2, (v_a[2]+v_b[2])/2]
        verts.append(mid)
        i = len(verts)-1
        mid_cache.update([(key, i)])
        return i

    faces_prev = faces
    for i in range(recursion_leve):
        # subdivide each triangle into 4 triangles
        faces = []
        for j in range(len(faces_prev)):
            v1, v2, v3 = faces_prev[j]
            a = get_mid_point(v1, v2)
            b = get_mid_point(v2, v3)
            c = get_mid_point(v3, v1)
            faces.append([v1, a, c])
            faces.append([v2, b, a])
            faces.append([v3, c, b])
            faces.append([a, b, c])
        faces_prev = faces

    # normalize vertices
    for i in range(len(verts)):
        x, y, z = verts[i]
        length = 1/(x**2+y**2+z**2)**0.5
        verts[i] = list(map(lambda p: p*length, verts[i]))

    msh = bpy.data.meshes.new("IcosphereMesh")  # Meshデータの宣言
    msh.from_pydata(verts, [], faces)  # 頂点座標と各面の頂点の情報でメッシュを作成
    obj = bpy.data.objects.new("Icosphere", msh)  # メッシュデータでオブジェクトを作成
    bpy.context.scene.collection.objects.link(obj)  # シーンにオブジェクトを配置


# delete existing meshs
for item in bpy.data.meshes:
    bpy.data.meshes.remove(item)

icosphere(2)

I refer to the following sites.

• http://blog.andreaskahler.com/2009/06/creating-icosphere-mesh-in-code.html
• https://observablehq.com/@mourner/fast-icosphere-mesh