We numerically model a doubly helical structure in a helically symmetric confinement,
which was recently experimentally observed. Due to helical symmetry we are able to
reduce the three-dimensional problem to two dimensions. Free energy is expanded
according to the Landau-de Gennes model and is discretized by the method of finite
differences. Minimization is done with gradient descent. We test the method on
physically relevant example of concentric and non-concentric domain. The doubly
helical structure is modelled on a adapted nephroid domain. The result is a double
twist director structure with the same sign and two localized defects in the two
trenches of the nephroid. We observe two twist disclinations
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