State to_left(&on_to_left_enter, &on_preview1, NULL);
State to_right(&on_to_right_enter, &on_preview2, NULL);
State settings;


void setup() {
    fsm.add_transition(&settings, &to_left, PREVIEW, NULL);
    fsm.add_transition(&to_left, &to_right, PREVIEW, NULL);
    fsm.add_transition(&to_right, &settings, SETTINGS, NULL);
}

void on_to_left_enter() {
    stepper.setTarget(500, RELATIVE);
}

void on_to_right_enter() {
    stepper.setTarget(-500, RELATIVE);
}


void on_preview1() {
    if (!stepper.tick())
        fsm.trigger(PREVIEW);
}

void on_preview2() {
    if (!stepper.tick())
        fsm.trigger(SETTINGS);
}