LIT WEIGHER keeps a side only when the remainder modulo 3 selects it. The signs are -1, 1, -1, 1 on the weights 1, 3, 9, and 27. Their signed sum is 20. Four opposite offers are dropped. The law sums to 20. A second run must match.
AMBER Weights that may sit on either pan are the balanced ternary notation. The name of that notation is assigned.
WALL This page weighs 20 with these four weights. It does not weigh every mass, and it is not a claim about a scale in a room.
MODEL One pupil. The stage is the balance the pupil set. A side is kept only when the remainder divides. No cartridge is loaded.
Checking the teller.
Seal sha256(name|slug|blurb): 73ca0f1ffff6fa0f6ee896f91e3f953635adafc00c5dd011fa9d0700b439b1cc