code: def loglike_shell(x):
      """gaussian shell, tilted"""
      # square distance from center
      r = ((x - 0.5) ** 2).sum()
      # gaussian shell centered at 0.5, radius 0.4, thickness 0.004
      L1 = -0.5 * ((r - 0.4**2) / 0.004) ** 2
      return L1
  
imports: import numpy
  from math import gamma, pi, exp
label_desc: Use image node_id 19 for calling a global function with example usage: loglike_shell(x) and returns: L1