L.A. Times Problem No. 180 by Sam Loyd. White mates in two.
FEN 7B/nQ6/2q2R1K/8/3k2P1/1B4P1/2R2Pn1/8 w - - 0 1
Key: ?Q-R7 and ?R-QB3
L.A. Times Problem No. 181 by A.C. White, Litchfield, Ct. From A.C.W. Flights of Fancy in the Chess World, 1919. This is easier than the average two-mover. Chex 'n double chex. A permissible key in this kind of novelty. Black uses all his sixteen pieces, white only four.
White mates in twelve.
FEN 2q5/2pp4/3pr3/4pb2/K1p2pn1/2bn1kp1/3pr1R1/6BB w - - 0 1
Key: 1. R-B2 d.ch; 2. R-B3 d.ch; 3. R-K3 d. ch and so on up the stairs. All double checks until the mate.