code: def _cone3d(shape, ij, pos, ampli, width):
      """Define a cone of the proposed grid"""
      temp = np.zeros(shape)
      pos = np.reshape(pos, (1, 3))
      dist = np.sqrt(np.sum((ij - pos) ** 2, axis=1))
      codi = (width - dist) * (dist < width) / width
      temp[ij[:, 0], ij[:, 1], ij[:, 2]] = codi * ampli
      return temp
  
file_path: nipy/nipy/labs/utils/simul_multisubject_fmri_dataset.py
imports: import numpy
  import scipy.ndimage
  from nibabel import Nifti1Image, save
  from nipy.io.nibcompat import get_affine
label_desc: Use image node_id 2 for calling a global function with example usage: _cone3d(shape, ij, pos, ampli, width) and returns: temp