Who amongst us hasn’t sketched a zombie-proof compound after being frustrated by a zombie film?
My favourite parts of that thought experiments were the agility tracks with thigh-high maze walls which humans can walk or run on, but which slow down zombies considerably, and the mechanical crushing sieve.
If you don’t want to take a considerable risk per destroyed zombie, you have to do the job at an arm’s length.
Fire and guns need too many resources per destroyed zombie, and axing them, even from a rampart, always poses a risk, of losing and having to retrieve your ax-head, if nothing else.
Enter the crushing sieve. You use the zombies’ own inexplicable capability to produce kinetic energy from seemingly nowhere, numbers, and a sound- or smell-based dummy bait, to press large crowds of zombies through a V-shaped stone or concrete formation.
The pressure of the zombies in the back forces the zombies in the front mechanically through a grinder of small openings. Zombies in, ground zombie flank out.