An FFGL mixer that wipes this layer in over the layer below the way an analogue vision mixer did: every pattern is a waveform built from ramps and parabolas and compared against the fader. Softness is the comparator's gain, so a circle's edge is softer near its middle where the parabola is flatter. The border is a second comparator, and modulation is a sine on the waveform.
This demo runs the plugin's shaders in your browser, so it needs JavaScript and WebGL2. The plugin itself, its source and its downloads are on its repository.