qmk-firmware/quantum/rgb_matrix_animations/cycle_pinwheel_anim.h

#ifndef DISABLE_RGB_MATRIX_CYCLE_PINWHEEL
RGB_MATRIX_EFFECT(CYCLE_PINWHEEL)
#ifdef RGB_MATRIX_CUSTOM_EFFECT_IMPLS

static void CYCLE_PINWHEEL_math(HSV* hsv, int16_t dx, int16_t dy, uint8_t time) {
    hsv->h = atan2_8(dy, dx) + time;
}

bool CYCLE_PINWHEEL(effect_params_t* params) {
    return effect_runner_dx_dy(params, &CYCLE_PINWHEEL_math);
}

#endif // RGB_MATRIX_CUSTOM_EFFECT_IMPLS
#endif // DISABLE_RGB_MATRIX_CYCLE_PINWHEEL