L.A. Times Problem No. 61 by Clif Sherwood, Los Angeles. L.A.A.C. Mercury, June, 1923. You'll get no cerebral hemorrhage from working this (which is shown mainly as a novelty for less experienced solvers. White mates in two.
FEN n7/3PP3/2NkB3/7n/1K6/8/8/6B1 w - - 0 1
Key: P-Q8(N)/d8=N
If N-B2 (self-block) 2. B-B5 mate. If N-N2 or B3; 2. B-R2 mate. Any other: 2. P-K8(N) double N promotion theme.
L.A. Times Problem No. 62 by Godfrey Heathcote. But here's one that may give even the experts a headache. White mates in three.
FEN b7/Kn1N4/3p3b/p2k1P2/Q3pp2/8/3PP1P1/8 w - - 0 1
Key: 1. P-N4/g4. If PxP e.p.; 2. P-Q4 Pxp e.p; 3. P-K4 mates. If N-B4; 2. N-N6ch K-K4; 3. Q-R mate! If P-B6; 2. P-Q4 etc. If P-K6; 2. P-Q3 etc. The showing of PxP 'in passing' on both first and second moves of black is another theme; a fine problem.