PlaneWaves is a simple kivy app displaying plane waves via GLSL shaders. You can click/tap to create wavevector markers and move them around to change the wavevector magnitudes. The superposition of all the wavevectors is displayed - you can see just the intensity, or the complex phase, or the phase modulated by intensity.

The app is under an MIT license (see LICENSE), either my own (main.py and planewave.kv) or that of the kivy project (shaderwidget.py).

The toast notification code is under an MIT license from knappador (github), see its code for more details.