"You keep on learning and learning, and pretty soon you learn something no one has learned before" Richard P. Feynman

three.js

Hello Cube
Examples

Shadow

Contact shadow (ground shadow)
RetAreaLight shadow
Progressive shadow

Ambient Occlusion

Screen Space Ambient Occlusion

Geometry

Boolean 3D operation (CSG)
Dimensioning arrow

GLTF Viewer

GLB/GLTF viewer

Frustum

Perspective Viewing Frustum

StackOverflow examples - three.js

BSP geometry - subtract cube

BSP geometry - subtract sphere

BSP geometry - subtract heart

geometry - extrude

Logarithmic depth buffer (cube)

Dashed line shader

Cube tilt (axis)