What a prism changes
In Prism Riddle, light changes direction when it enters and leaves a glass prism. Different wavelengths bend by different amounts, so a white beam can spread into a spectrum. The orientation of the glass changes which surfaces the light meets and the angle at which it leaves. A small rotation can therefore move the entire spectrum across the chamber.
This makes a prism puzzle different from a simple mirror maze. A mirror turns a beam while preserving its wavelengths. A prism can send those wavelengths along slightly different paths. You need to consider where the spectrum will arrive, which part can pass an opening and which colors a gate will accept.
Play the two-color refraction puzzle
The challenge above gives you a fixed lamp, one rotatable prism and two small gates. R accepts red light; B accepts blue light. Rotate the prism until both readings satisfy their power and color-purity requirements. A beam that looks close can still miss a gate, so use the live table to distinguish an aiming problem from a color problem.
Keep white light selected while solving. After finding a working angle, try Red band only or Blue band only. Refraction can redirect the wavelengths present in the source, but it cannot generate the other band. This is why two separately colored targets make dispersion part of a puzzle instead of just a rainbow effect.
This mini challenge is free and does not count toward your 80-chamber record. You can reset it freely, send the scene into Free lab, or continue to the third free chamber, where the prism is one part of a longer route.
Why moving a prism matters as much as rotating it
Two prisms at the same angle can produce very different results if one sits higher or farther from the next instrument. Changing its position changes where the incoming beam meets the glass and how far the separated rays can travel. A spectrum that is compact near the prism can be much wider when it reaches a distant mirror.
Start by placing the prism across the beam. Watch the outgoing light while you rotate slowly. Once it points toward the correct part of the chamber, adjust its position to make the next mirror or opening useful. The light is always calculated from the current arrangement, so you can test each idea immediately.
Combine a prism with a mirror or lens
A mirror can catch a slanted spectrum and carry it through another part of the ruins. Its angle needs to match that slanted input; a familiar angle from an earlier white-light puzzle may not work here. A lens can change the width of the rays after the turn, helping the useful wavelengths reach a small gate lens.
The third free chamber, The Hidden Spectrum, combines a lower mirror route, a prism, an upper mirror, a lens and a filter. It introduces dispersion as part of a complete route, rather than as an isolated color effect.
A filter removes colors; it does not invent them
White light contains several wavelength bands. A green filter passes the green part and absorbs most of the rest. It cannot turn a purely red input into a green beam. That distinction matters when a gate requires both a clean color and enough energy: filtering a badly positioned spectrum may leave almost nothing to collect.
Read the color-purity indicator together with the energy indicator. A clean but weak beam and a bright but mixed beam can both fail the same gate for different reasons. The appropriate fix depends on which condition is missing.
Three variables control a useful spectrum
| Variable | What it changes | Useful observation |
|---|---|---|
| Prism position | Where the incoming beam meets the glass | Move it until the full beam enters one face instead of clipping a corner |
| Prism rotation | Entry angle, exit direction and separation | Rotate slowly because a small change moves every wavelength |
| Travel distance | How far the colors spread before the next tool | A distant mirror can select a narrower part of the spectrum |
Splitting a spectrum is an energy problem too
Later puzzles may ask for two colors at different gates. A prism can separate wavelengths, but a beam splitter still divides the energy that reaches it. The order of the tools matters: splitting white light and then filtering each branch can behave differently from separating the spectrum first and placing each branch where it already contains the useful color.
When two colored gates must open together, compare both energy bars after every change. Improving one route can starve the other. A balanced solution often uses cleaner geometry rather than another filter.
What makes a prism light game different?
A prism light game makes color part of the geometry. The path is not only a center line: it has width, wavelength and energy. Red, green and blue portions can leave the same prism at different angles, spread farther apart over distance and reach different parts of the chamber. That gives a puzzle several possible jobs for the same prism—turn the whole beam, create enough separation for a filter, or aim two colors toward different branches.
Prism Riddle combines those color decisions with obstacles and optical tools. A beam may need to reflect before entering the prism, pass through a narrow opening after dispersion and then be focused onto a small gate. The third chamber is free so the core prism puzzle can be tried before unlocking the larger collection.
What the game simulates
The game uses finite-width geometric light sampled across 27 wavelengths. It includes wavelength-dependent refraction, reflection, splitting and filtering, with a near-axis thin-lens approximation for lenses. Glow and texture make the light visible; they do not create additional energy. Free lab also offers a specified three-order diffraction grating and polarization models. Coherent interference between separate light paths and a full wave-optics simulation are outside the model.
For a reflection-only starting point, try the free mirror puzzle game. To compare related mechanics, explore Prism Riddle’s light puzzles or the diffraction grating experiment. A grating and a glass prism separate colors through different physical mechanisms.
For background on the underlying phenomenon, see the OpenStax introduction to refraction. To explore it directly, start the free prism chamber or open the workshop.