Kinetic Prism: The Missing Axis

About Kinetic Prism: The Missing Axis

Kinetic Prism: The Missing Axis is a spatial programming puzzle set in an abandoned museum of inventions. On a plinth under dust sheets an exhibit is missing, and only its two shadows are left on the walls: the front shadow, which shows the tallest stack in every column, and the side shadow, which shows the tallest stack in every row. The view from above, the plan of which cells hold blocks, is the missing axis. Many different heaps cast the same two shadows, and you have to decide which one to build.

You never place a block by hand. A small brass automaton, the Docent, builds the exhibit from a paper tape. You punch cards onto the tape: step forward onto a bare cell, turn left, turn right, or place one block on the cell in front. Press Run and the Docent carries them out in order while the dust sheets lie still. It cannot climb, so it can only walk on bare floor; a pillar blocks it, and a stack has a height limit. The exhibit is finished the moment both shadows match. The game's own solver finds the shortest program of any heap that casts them: that is par, and a heap that looks right can cost many more cards than one that is cleverly placed.

There is no clock and nothing to lose. A wrong tape costs nothing: take a card off, swap one, or clear the tape and run it again, and after a run every column and row of the shadows shows whether your heap matched it. Twelve hand-made exhibits grow from a flat plinth and one tall stack to three-high heaps with pillars crowding the floor. Beyond them are attic exhibits seen from the other side of the room and a daily exhibit that is the same for everyone. When both shadows match, a gas lamp swings on, the silhouettes fall bright on the walls, the dust sheets slip off the neighbouring cases and a music box begins to play. Hints are always there, and your progress stays in this browser.

How to play

Build a heap whose two shadows match the walls. You do not place blocks yourself: you punch cards onto a paper tape, then press Run and watch the Docent build.
Tap a typewriter key (or press Up to step, Left and Right to turn, Down or E to place) to punch a card. The Docent steps only onto bare floor and places a block on the cell in front of it.
The front shadow shows the tallest stack in each column; the side shadow shows the tallest stack in each row. Many heaps fit, so choose one that is quick to build.
A pillar blocks the Docent and a block cannot be placed on it. A stack holds only so many blocks.
Solve an exhibit in par cards with no hint for three stars. A wrong tape costs nothing: edit and run it again.

Controls

Tap a typewriter key, or Up or W — step; Left and Right, A and D, D-pad — turn; Down, S, E or Ⓐ — place a block
Space, Enter, Ⓧ or Run — run the tape; Backspace or Back — take the last card off; Delete or C — clear
Z or U — undo an edit; Y — redo; H or Hint — a hint; B — hear the exhibit described again
P, Escape or Start — pause

Frequently asked questions

What is the missing axis?

You are given two shadows, the front one and the side one, but not the plan from above. Many heaps of blocks cast the same two shadows, so you must reason about which cells to fill. The view from above is the axis nobody shows you.

How do the shadows work?

The front shadow is the tallest stack in each column of the plinth, left to right; the side shadow is the tallest stack in each row, top to bottom. Both must match exactly, and a stack taller than the shadow allows spoils it.

How does the Docent move?

It steps one cell forward onto bare floor only (it cannot climb a stack), turns a quarter left or right, and places one block on the cell in front of it, if that cell is on the plinth, free of a pillar and not at the height limit. A card that cannot do its job is spent and nothing happens.

How are stars and par worked out?

The game's own solver finds the shortest tape of any heap that casts both shadows: that is par. Par cards with no hint earn three stars, one more earns two, any solved exhibit one; an exhibit solved after a hint earns at most two.

Is it timed?

No. Nothing is timed, and a wrong tape costs nothing: change a card and run it again.

Does the game save?

Yes, in this browser: solved exhibits, stars and the tape of the exhibit you were working on. Nothing is uploaded.