The History of Sorting Puzzles
Moving pieces between holders by fixed rules is an old idea in puzzles - the Tower of Hanoi did it in 1883.
Pieces, Pegs and Rules
Puzzles in which pieces are moved between holders by fixed rules are old. The Tower of Hanoi, published by the French mathematician Édouard Lucas in 1883, has discs moved one at a time between three pegs, never a larger disc on a smaller one.
Sorting by Kind
In recent years many puzzles have appeared in which mixed pieces are moved between containers until each holds only one kind - mostly as games for phones and almost always with colours. On a black-and-white e-ink screen colours do not work, so PaperGames sorts shapes instead.
How PaperGames Makes Each Puzzle
Every puzzle here is dealt at random. A solver then searches for a way to sort it completely; only a deal for which it finds one is used, and no tube starts out already finished. The same solver gives the hints.