code: def mini_mesh() -> PolyMesh:
      """Small mesh for tests with 2 parts with different numbers of vertices."""
      left_coords = np.asarray(
          [[0.0, 0, 0], [1, 0, 0], [0, 1, 0], [0, 0, 1]]
      )
      left_faces = np.asarray(
          [[1, 0, 2], [0, 1, 3], [0, 3, 2], [1, 2, 3]]
      )
      right_coords = (
          np.asarray(
              [[0.0, 0, 0], [1, 0, 0], [1, 1, 0], [0, 1, 0], [0, 0, 1]]
          )
          + 2.0
      )
      right_faces = np.asarray(
          [
              [0, 1, 4],
              [0, 3, 1],
              [1, 3, 2],
              [1, 2, 4],
              [2, 3, 4],
              [0, 4, 3],
          ]
      )
      return {
          "left_hemisphere": InMemoryMesh(left_coords, left_faces),
          "right_hemisphere": InMemoryMesh(right_coords, right_faces),
      }
  
file_path: nilearn/nilearn/experimental/surface/tests/conftest.py
imports: from typing import Callable
  import numpy
  import pytest
  from nilearn.experimental.surface import InMemoryMesh, PolyMesh, SurfaceImage, load_fsaverage
label_desc: Use image node_id 1 for calling a global function with example usage: mini_mesh() and returns: dict