  We present a mixed reality application (HoloFEM) for the Microsoft HoloLens.
The application lets a user define and solve a physical problem governed by
Poisson's equation with the surrounding real world geometry as input data.
Holograms are used to visualise both the problem and the solution. The finite
element method is used to solve Poisson's equation. Solving and visualising
partial differential equations in mixed reality could have potential usage in
areas such as building planning and safety engineering.
