PRISM: Light Puzzle

Tap, and the light bends.

PRISM is a puzzle with exactly one rule. Tap a piece and it turns 90 degrees;
the light instantly finds a new path. Light every crystal with precisely the
color it asks for, all at once, and the board is solved.

The controls need no explanation — one tap is all there is.
If you want to know how light actually works, that is in here too.

■ Six chapters, 240 puzzles

I. Reflect — mirrors turn light by 90 degrees
II. Split — a half-silvered mirror passes light and reflects it at once
III. Disperse — a prism breaks white light into red, green and blue
IV. Mix — two beams meeting at one crystal become a new color
V. Refine — filters keep only what you want. Overshoot and you fail
VI. Converge — everything you have learned, on one board

■ Every puzzle has exactly one answer

All 240 levels were machine-proven to have precisely one solution before
shipping. No configuration works by accident, and no piece is decoration —
rotate any of them and the solution breaks. The par shown on each level is
not an estimate either; it is the true minimum, found by exhaustive search.

■ Nothing gets in your way

· No ads
· No in-app purchases
· No account, no sign-in
· No networking — the app never asks for internet access
· No data collected
· No lives, no energy, no timers
· No locked levels — stuck? just move on to the next one

You buy it once. That is the whole transaction.

■ This is real optics

The angle of reflection, dispersion through a prism, additive color mixing,
selective absorption in a filter — every rule in this game comes from real
physics. Entering a new chapter shows you the principle behind it on a single
card. Tap once to dismiss it, or read them all later under "How light works".

It also states plainly where the game simplifies the physics.

■ If color is hard for you to tell apart

Every crystal carries its required color as a shape as well.
Red is a triangle, green is a square, blue is a circle. A yellow crystal
shows a triangle and a square side by side. You can finish every puzzle
in this game without seeing color at all.

■ About the sound

The pitch of each rotation depends on where the piece sits on the grid —
higher toward the top, lower toward the bottom. Solving a puzzle turns your
hand into a short melody. It only uses a pentatonic scale, so no order of
taps can sound wrong.

Turn the sound off and haptics take over the same job.

■ It is light

Nothing you see or hear was authored as a file. Apart from the app icon there
are no images and no audio inside; every beam of light and every note is
computed as you play. All 240 puzzles compress to 9 KB of data.