Filter sierpinski
  Render a Sierpinski fractal.
    slice threading supported
    Inputs:
        none (source filter)
    Outputs:
       #0: default (video)
sierpinski AVOptions:
  size              <image_size> ..FV...... set frame size (default "640x480")
  s                 <image_size> ..FV...... set frame size (default "640x480")
  rate              <video_rate> ..FV...... set frame rate (default "25")
  r                 <video_rate> ..FV...... set frame rate (default "25")
  seed              <int64>      ..FV...... set the seed (from -1 to UINT32_MAX) (default -1)
  jump              <int>        ..FV...... set the jump (from 1 to 10000) (default 100)
  type              <int>        ..FV...... set fractal type (from 0 to 1) (default carpet)
     carpet          0            ..FV...... sierpinski carpet
     triangle        1            ..FV...... sierpinski triangle


