- The following presents a list of puzzles alongside the general goal of the puzzle and any additional rules present.
- Although some degree of Mathematics is present for all of these. We exclude mathematical problems.
Dissection Puzzles
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Cut a shape into smaller shapes and re-arrange them to produce a particular pattern or geometric shape
- Extension: Frame the problem as going from one shape to another shape while using:
- The fewest / given number of cuts.
- The fewest / given number of shapes
- Extension: Go from one shape to many smaller target shapes. Adding additional constraints (i.e., each smaller shape is the same size)
- Extension: Go from many given shapes to one target shape.
- Extension: Frame the problem as going from one shape to another shape while using:
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Disappearance Puzzles - arrange the geometric shapes in such a way that in the resulting shape, there is an apparent addition / subtraction of units.
- Alternatively, explain where the sleight of hand is in the disappearance
Tangram-Like Puzzles
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Tangram - starting with a set of pieces of different shapes, assemble various figures based on their silhouettes.
- The STANDARD set is 5 triangles of varying sides + a square and a rhomboid.
- Extension: Circular Tangram - generalizes Tangram to use pieces that can have curved sides.
- Extension: Use a different set of given shapes.
- Usually, though, the pieces can be assembled to form a basic shape (a square, circle, heart, egg, etc…)
- The player is given a silhouette.
- We can make it harder by obstructing the silhouette non-intrusively (adding stripes, for example).
- Silhouettes can be abstract to representational, pertaining to people or objects. Sometimes even these objects may be given in place of the silhouette.
- The player MUST use all pieces to assemble the figure.
- In assembling, the pieces MUST touch without overlapping.
- The STANDARD set is 5 triangles of varying sides + a square and a rhomboid.
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Polyforms - Similar to Tangram except with the additional constraint that all pieces are identical or similar in some way. The goal is still to produce a similar shape.
- Polyomino problem - a variant using a polyomino (usually a pentomino). Given a set of polyominos, cover the silhouette of the shape without the pieces overlapping.
- Extension: Add a constraint where certain patterns may not be produced (for example, four polyominos may not touch at a corner).
- Extension: Not just 2D shapes, but use 3D shapes too with varying thicknesses.
- Soma Cube Variants - given a set of 3D polycubes (cubes assembled in a particular 3D shape), make a bigger cube (or a bigger shape) using all the pieces.
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Matchstick Puzzles - Similar to Tangram except with the additional constraint of all pieces corresponding to sticks (aka edges). The goal is still to produce some shape.
- Extension: We may only operate on a limited number of moves.
- Extension: Move matchsticks to produce another configuration.
- Extension: Remove matchsticks to produce another configuration.
- Extension: Allow / Forbid matchsticks to be broken
- Extension: The matchsticks are of different lengths.
- Extension: Allow / Forbid matchsticks to cross.
- Extension: The matchsticks must make a 3D structure that satisfies additional constraints.
- Extension: We may only operate on a limited number of moves.
Miscellaneous Types
- Domino Puzzles - puzzles that involve the use of dominoes---defined as a piece consisting of two half-tiles. Each half tile has a number of pips on them.
- Variant: Make a pattern given a set of dominoes such that half-tiles that touched each other had the same number of pips.
- Variant: Make a pattern such that the “rows”, “columns” or both satisfied an arithmetical constraint (i.e., same sums)
- Extension: Whether or not to allow dominoes with blank half-tiles and how to handle them exactly.
Logic Puzzles
- Any form of mathematical puzzle counts here.
Grid Puzzles
Positioning Puzzles
- Chessboard / Checker Puzzles
- Involve the use of a chessboard, usually exploiting the property of having white and black cells.
- Alternatively, it may involve the use of circular checker pieces that slide around each other in a certain way. The goal is to arrange them in a new way.
- Constraints on movement may also take inspiration from chess moves or checker moves.
- Connection Problem
- Form a Graph that connects a set of nodes together, satisfying some sort of property.
- Moving Peg Puzzles
- An array of holes is drilled in a board. White pegs are placed in the upper half. Black pegs are placed in the lower half. The center is left vacant.
- The goal is to transfer the white pegs to the lower half and the black pegs to the upper half.
- A peg may move either
- to an adjacent vacant square or
- by jumping over one neighboring peg to a vacant square
- Moves must only be forward or backward, parallel to the sides of the square.
- Peg Solitaire
- We have a board full of pegs arranged in some way.
- Pegs can only be moved by jumping over a neighboring peg to a vacant space directly on the other side. Following this jump, the peg that was jumped over is removed.
- Jumps are only made along lattice lines.
- The goal is to remove all pegs on the board.
- Transportation Puzzle
- We have a set of objects and two (or more) islands with a river separating them.
- The goal is to move all the objects to the other side of the river.
- Certain objects cannot be together.
- Example: Tower of Hanoi
- Example: Farmer, Fox, Rabbit, Cabbage Problem
- Shunting Problem
- Given trains on a set of railroad tracks, find a way to get the trains to where they are supposed to go without them colliding.
- Constraints on the number of moves or the time taken may be given.
- Variant: The length of the track may influence the number of rolling vehicles which can be placed on them.
- Variant: Certain trains may not go on certain tracks.
- Variant: Build up a train in a specific order, picking up rolling stock from various locations.
- Variant: Decompose the train, placing rolling stock items in specified locations.
- Variant: Devise the optimum sequence of rolling stock items in a train, so that it can be efficiently assembled at its starting point and decomposed at its destination(s).
- Sliding Block Puzzle
- Consists of a set of blocks arranged on a board. The blocks can slide around.
- The goal is to arrange the blocks in a certain way.
- Pieces CANNOT be lifted off the board.
- Example: The 15 Puzzle
- Example: Sokoban
Mechanical Puzzles
- Packing Puzzle - the goal is to fit two items together, but the way they fit together is not as straightforward. The solver must determine how to fit them together.
- Example: The Melting Block
- Example: Conway’s Packing Problem
- Example: The Chinese Cube
- Example: The Vanishing Sphere
Disassembly Puzzles
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The challenge for these puzzles is not only to solve it, but to undo the solution (i.e., to reassemble the problem)
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Burr Puzzle - also called Chinese crosses or Notched stick puzzles. Consists of structures that interlock with each other. The goal is to disassemble the structures.
- Example: Van der Poel’s puzzle,
- Example: The Japanese Crystal
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Magic Boxes - the goal is to unlock the box. The lock has complex mechanisms that the solver must determine and unlock.
- Example: Haselgrove Box
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Magic Disk - consists of interlocking disks that must be separated from each other.
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Rattle Puzzle - consists of a container with an item inside that would rattle when the container was shaken. The goal is to remove the item(s) inside.
- Example: The Ball in the Cage
Ring String Ball Problems
- Features any two of a ring, string (solid rod or cord), and a ball. The goal is:
- Variant: Remove one element from the puzzle.
- Variant: Move one element with respect to the main component.
- Variant: Find the sequence of moves such that one part is removed or repositioned.
- Variant: Solve the puzzle with additional constraints (i.e., the cord and the ring must stay together).
- Generally when a string is used, the key is generally to be found in a loop drawn over a knot or ball.
- Example puzzles are found in Van Delft and Botermans.
- Maleda - the goal is to remove the staple by raising the rings and rods in a certain order.
String Puzzles
- Whai / Cat’s Cradles - the goal is to form intricate patterns using only string held taut by one’s fingers.
- Generally feature strings where the objective is:
- Variant: Rejoin two ends of the string.
- Variant: Perform a cut on the string that obeys certain constraints.
- Variant: Pull at the string in a certain way so that knots vanish.
- Variant: Unknot the cord (can be extended further to escape from bonds.)
- Variant: Perform an intricate knot subject to constraints.
Wire Puzzles
- Wire Puzzles - a similar variant to the Burr Puzzle except involving metal pieces that have been bent and interlocked with each other in a convoluted manner.
- Example: A famous one — the Gordian Knot
- Variants of this can incorporate elements from Ring String Ball Problems
- Wire and String Puzzle - consists of a wire and a string (with possibly additional components like balls or knots).
- Closed String Puzzles - the string consists of one closed loop. The goal is usually to disentangle the string from the wire.
- Unclosed Loose String - the pieces of the string are not closed and not attached to the wire. Usually the ends are fitted with an object to keep the string from slipping out.
- Unclosed Fixed String - the pieces of the string are not closed, but somewhere on its length is attached to the wire. The goal here is usually similar to a string puzzle.
Tour Puzzles
- The puzzle involves the player traveling around a board, possibly requiring the player visit certain points on the board.
Mazes
- Patterns of intricately winding paths have been cut on the landscape. The goal is to navigate from point
to point , traversing through the maze. - A classic technique to solving this (which doesn’t always work) is to keep your hand on one side of the maze at all times.
- This fails when there is more than one entrance and there is a route connecting them that doesn’t pass through the goal, or if there are loops
- Another technique by Tremeaux (which is just DFS in disguise)
- Mark one side of the corridor (say the right) as you pass through the maze.
- Whenever you reach a dead end, retrace your steps, still marking the right hand wall.
- Whenever you reach a previously visited junction along a path that you are following for the first time, turn around and retrace your steps, still marking the right hand wall.
- When you reach a previously visited junction along a path that you have used before, take a new path. If there is any available. Otherwise, take any previously used path.
- Never enter a path that has been marked on both sides.
- Other methods make use of Graph Algorithms.
- When making a maze, it is usually best to start with the solution path first.
- Variant: 3D Mazes
- Variant: More than one goal (that may need to be reached in a specific order)
- Variant: More than one entrance.
- Variant: Entrance and or exit is inside the maze rather than the typical case where they are outside.
Optimization Puzzles
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Applies to any of the puzzles above (or to new ones).
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Instead of being given the number of moves, find the optimal number of moves that still solve the problem.
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This also extends to tasks that are adjacent to Automata or Assembly wherein we want to minimize:
- The number of instructions
- The “space” occupied by the solution (analogues to memory or size for example).
- The time it takes for some program to finish.