This ‘4 whistle' is 4 whistles all sharing the same mouth piece. 2 of of the same length and 2 are shorter or longer. So there are 2 whistles at the same tone beating against each other in sync and then two whistles at slightly different frequencies out of phase going in and out of beating interference.
It is not loud. Just blow softly. It sounds sort of like an old english police whistle.
20% infill and no supports at 0.2mm layers. ~1 hour. Yellow PLA example is my ender 3 v3 se. White PLA example is a friend's bambu printer.
The author marked this model as their own original creation.