#3 Laws, Benjamin Glover
The Problemist January 1926

The solution to Monday’s problem is 1. Qh8.

This move threatens 2. Bc3+ followed by 3. Qd4#.

If Black now plays 1… Kxc5, White still plays 2. Bc3, with Qd4# to follow, unless Black runs with 2… Kd6, when 3. Qf8# (a switchback) follows.

The only other defence is 1… a2, when 2. Bb2 is now available, threatening 3. Qc3# and meeting 2… Kxc5 with Qd4#.

Simple for a mate in 3, but rather neat. Solving problems like this on a regular basis will improve your tactical ability.