How to play × Drag optical pieces to move them. Drag a fixed source to aim it. Select a piece, then drag its dotted arc or use the rotation buttons. Direct enough light of the required color into every receiver.
Mirror: reflects at equal angles.Lenses: convex focuses; concave spreads. Concave mirrors concentrate reflected rays; convex mirrors spread them.Prism and glass: refract by wavelength.Splitter: sends light down two paths.Black hole: drag its ring handle or use − / + to change its horizon size and mass. It curves nearby light and absorbs rays at its core.Campaign inventories are fixed: no adding or removing pieces. Sources are anchored, and their power and spectrum are locked unless the puzzle explicitly allows spectrum changes. Objects marked FIXED cannot move or change. Anchored optics may still rotate or allow tuning. Free play removes these restrictions. Select adjustable glass to change its refractive index.
Targets: each target fills its own ring after three seconds of suitable light, independently of the others. A charged target stays powered only while illuminated. Losing its beam resets only that target; other targets keep their charge. The level completes when every target is charged and still powered. Heat targets also need to remain hot enough. Power switches: the lightning symbol stays on only while illuminated; its gate closes when the light stops.
Spectrum and heat: select a source to enable bands and set power per band. X-ray (0.1 nm), UV (300 nm), and thermal IR (10 μm) use false colors. All absorbed radiation heats materials; equal absorbed power produces equal heat. Heat is shown in relative units, with cooling over time.
Material transmission is simplified for these representative bands: ordinary glass absorbs much of UV and thermal IR, thin masonry partly transmits hard X-rays, and lead strongly attenuates them. Coefficients are tuned for play. Gravity bends every wavelength equally; it does not sort colors like a prism. Multiple black holes use an approximate combined field.
Beyond visible: radio (cyan) and microwaves (amber) use illustrative ray paths, without diffraction or interference. Microwaves are part of the radio spectrum; the two controls represent different example bands. Dielectric walls partly transmit them; metal blocks them. Transmission depends on the material and frequency, and coefficients here are tuned for puzzles. UV-excited coatings emit a visible green glow and reveal their outlines. Heat-sensitive sensors are permanently damaged at their marked limit: Reset to retry. Contamination detectors reject every unwanted band, including invisible ones.
Point emitters: radiate outward with spherical inverse-square spreading projected into the 2D playfield. Collectors capture a finite bundle; lenses then collimate or concentrate it. This is a geometric-optics approximation, not a full 3D wave simulation. RF lenses are engineered radio optics. Visible-pass filters are idealized selective filters. Long-range radio stages zoom out to show a larger physical playfield.
Heat & matter: black-body spectra are integrated from Planck’s law; net emission uses a 300 K environment and wavelength-dependent emissivity equal to absorptivity. Specimens use a schematic 4 mm² radiating area and accelerated heat capacity. Kelvin is absolute temperature. Coatings and dyes use illustrative coefficients, not measured material data. Fluorescence conserves energy using quantum yield and the excitation/emission wavelength ratio, with one simulation-frame latency. Discharge lamps have separate electrical supplies; an optical switch controls them. Their selected line wavelengths are grouped into broad bands for tracing. Diffuse reflections and secondary emission use the same projected inverse-square spreading as radial sources, until collected by focusing optics. Everyday objects are schematic surface samples, with illustrative RGB reflectances. Their icons identify the specimen; the rays show the reflected spectrum. Thermal specimens visibly glow only according to their emitted visible bands, while infrared retains a false-color overlay. Faint secondary emission is visually amplified; target meters use unamplified power. The broad IR band does not resolve near-IR versus thermal-IR transmission, and conduction, geometry and scattering are simplified.
Blackbody physics · Fluorescence & discharge · Neon lines (NIST)
Space spectroscopy: selected H I, He I, Na I, Ne I and Ca II line positions come from the NIST Handbook . Tabulated air wavelengths are approximately converted to vacuum wavelengths using standard-air refractivity. Fine structure is represented by selected components. Source line strengths, gas populations, optical depths, Cauchy prism coefficients and slit-resolution scale are illustrative. Star light is sampled only over 380–720 nm. Emission gas samples have external excitation supplies. Absorption cells remove light from the viewing beam; diffuse resonant scattering is omitted. Hydrogen Balmer and visible helium/neon absorption require excited lower states; sodium D and Ca II H/K are resonance transitions. Planet lessons isolate atmospheric limb transmission, not a full transit model. See NASA’s spectroscopy guide .
Press Space to pause motion, heat, and charging. Light and matter · Microwaves · Ultraviolet · Black holes
Let's play →