The front piece of a battery makes an ambush move and becomes the rear piece of a newly created battery.
Meinking, Dan
StrateGems, P. Petkov-60 JT, 2002
Spec. Prize
1...Rc4
2.Kd5
Ra4+
3.Ke4
Ra3
4.Kf3
Bd5#
1...Bc4
2.Kc5
Be2+
3.Kb4
Bd1
4.Ka4
Rc4#