---
name: Shadows
slug: shadows
type: optical-phenomenon / psychological-artifact
status: running
version: 4.6e9
released: "~3.8 billion BCE"
maintainer: physics (delegated to local star geometry)
dependencies:
  - light-source
  - occluding-object
  - receiving-surface
  - time
license: Public Domain (cannot be owned, though many have tried)
tags:
  - optics
  - absence
  - fear
  - geometry
  - daily-life
  - horror-trope
---

Shadows

What it actually is

The exact shape of what blocks light, rendered in its absence.

How it works

A shadow is not a thing. It is the subtraction of a thing. When a light source, an occluding object, and a receiving surface achieve a particular geometric alignment, the surface reports: something was here, between us. The shadow is that report.

Length is a function of angle. At noon, shadows are honest and short. At dusk, everything becomes a monster. This is not metaphor. This is trigonometry.

Two zones exist in any well-formed shadow:

Umbra: the full absence. The light source has no opinion here.
Penumbra: partial occlusion. The ambiguous zone. Most psychological damage occurs here.

Features

Scales linearly with distance from occluder to surface
Preserves silhouette fidelity (lossless edge compression at hard light sources)
Moves in real time with no rendering lag
Available in grayscale and color (subsurface scattering environments only)
Compatible with all surfaces: skin, concrete, memory, water
Requires no power. Runs on existing stellar infrastructure.

Known bugs

Shadow self: your own shadow follows you everywhere and cannot be detached. Attempts to do so are well-documented in folklore and uniformly fail.
Umbraphilia: prolonged shadow environments may trigger melancholy in susceptible users. Not a bug per se. Flagged anyway.
The uncanny silhouette: shadows occasionally misrepresent the occluder. A coat on a hook at 3am renders as a standing figure. Working as intended, technically.
Shapeshifting near edges: penumbra zones produce soft, unresolved forms. Users find this more disturbing than total darkness.

Edge cases

Scenario	Behavior
Two light sources	Two shadows. Neither feels like the real one.
Diffuse overcast sky	Shadow nearly absent. Objects lose gravity.
Solar eclipse	Shadow of the moon lands on Earth. See: awe.
Interior of a black hole	Concept does not compile.
Grief	Shadow persists after occluder is removed. Known issue.

Configuration

shadow_defaults:
  hardness: 0.0 – 1.0       # 0 = overcast, 1 = solar noon in desert
  direction: sun_angle       # auto-calculated, not user-configurable
  color: "#1a1a2e"           # approximate. varies by surface and mood
  opacity: 0.6               # adjustable by clouds, atmosphere, trauma
  cast_by_memories: true     # cannot be set to false

FAQ

Can I live without shadows? Only in conditions of total diffuse light, which feel deeply wrong to most mammals. Shadows are how depth proves itself.

Why are children afraid of them? They are not wrong to be. A shadow is proof that something is between you and the light. Children simply haven't learned to pretend this is fine.

Why do artists need them? Without shadows, form is a rumor. Shadows are what make objects legible as solid, present, and real. Painters learned this before physicists bothered to explain it.

Is my shadow me? It is the part of you that the light cannot reach. You decide if that counts.

drafting spec…