Another fun setup, from a C4D thread (Houdini scene file attached below):
houdini_6Y6BwBfK7E.mp4
This scales really well, too. Here it is with 12 thousand arrows, playing in real time in the viewport, on my 7-year old machine. Not sure what that would ever be useful for, but still pretty cool to see in action (the FPS is displayed in the bottom right - green means real time):
houdini_pk5I6C4dpk.mp4
This is the C4D thread:
Arrow wave modeling and rendering translucent planes - Cinema 4D - Core 4D Community
Arrow Waves.hiplc