attract live v += û · (1 − d/r)² · S · 0.5 (+ orbital swirl) A soft gravity-like well, optionally bent into a spiral.
A hero word that pulls the field into orbit around it.
API reference
The 34 forces
Compose them on any data-body element, space-separated. Each card is generated
from the engine's own catalog — the law, the attributes it reads, and a real-world use.
Canonical nine
The bounded, UI-legible verbs — what a body does to nearby matter. (9)
repel live v −= û · (1 − d/r)² · S · 0.5 Soft outward push — carves a void.
A dismiss control that opens a clean void in the field.
swirl live v += û⊥ · (1 − d/r)^1.4 · S · 0.45 · spin (+ 0.12 inward) Tangential swirl with light inward retention.
A loading state that spins the field into a swirl.
stream live v += ĥ · (1 − d/r)^1.1 · S · 0.5 A steady directional current along a heading.
A scroll cue that combs the field downwind like a current.
viscosity v −= v · (1 − d/r) · (0.05 + 0.07·S) Viscosity — thickens the medium, bleeding momentum.
A modal backdrop the field thickens behind — motion settles.
jet feed: v += û·(1 − d/r)²·(0.25 + 0.15·S); at the nozzle (<24px): relaunch as a jet A conduit — draws matter in, jets it out along a heading.
A call-to-action that draws matter in and jets it back out.
tether live v += û · (d − rest) · k; v *= 0.985, rest = 0.6·r A tether with a rest length — holds matter at a shell radius.
A pinned element the field tethers to at a rest radius.
wall inside box: push out the shallower axis, v_axis ← −0.85·v_axis An axis-aligned bouncing wall — sparks on hard impact.
A card the field bounces off — a wall that sparks on impact.
sink capture within absorbR; at capacity, release everything (supernova) Captures matter, holds it (conserved), then releases it.
A cart that accretes matter, then releases it on checkout (a supernova).
Natural primitives
Real physical laws in a consistent unit system. (8)
gravity live F = G·M·d̂ / (d² + ε²), ε = r_s = 2GM/c²; |v| ≤ c True softened inverse-square — a real 1/d² law.
A heavy headline with a true 1/d² pull — a real well.
charge F = −σ·q·GM·d̂ / (d² + ε²) The signed sibling of gravity — like repels, opposite attracts.
Two states that demix charged matter into +/− domains.
magnetism v ← rotate(v, θ), θ = q·spin·B·(1 − d/r) The Lorentz force — curves a moving charge, doing no work.
A region that curves moving charge into cyclotron arcs.
thermal v += √(2T) · ξ, T = S·(1 − d/r), ξ ~ N(0,1) per axis Langevin/Brownian agitation — a real temperature in the medium.
A "hot" badge that agitates the field with Brownian heat.
collide overlapping, approaching discs exchange normal momentum (e = S) Elastic pairwise collision — the hard-sphere billiard force.
A dense cluster where particles ricochet like billiards.
diffuse deposit φ; v += ∇φ · S; field blurs ∂φ/∂t = D∇²φ A pheromone field — deposit a mark and follow the diffused gradient.
A trail particles lay down and follow — stigmergy.
propagate pulse φ at the source; v += r̂·|∇φ|·S (ride the front out); ∂²φ/∂t² = c²∇²φ A travelling wave — particles ride the expanding front.
A button that fires a real shock wave across the field.
memory M(x) += λ where matter sits; v += û · (1 − d/r)² · S · 0.5 · (1 + μ·M) The field remembers — occupancy wears in paths that pull harder.
A frequently-used path that wears in and starts pulling harder.
Designed extended
Pure per-particle effects — bends, gates, phase changes, modifiers. (17)
lens v ← rotate(v, θ_max · (1 − d/r) · sign) Rotates velocity, preserving speed — bends paths without adding energy.
A link that bends a passing flow into caustics — no capture.
gate if v·n < 0: v −= 2(v·n)·n A one-way membrane — passes along its heading, reflects the reverse.
A one-way membrane: matter passes through but not back.
buoyancy live v_y −= (ρ_med − ρ_p)·g, ρ_p = base / (size·(1 + heat)) A constant lift/sink by density — light matter rises, dense settles.
A feed where light/hot items rise and dense ones settle.
shear v∥ += S · (offset⊥ / r) · (1 − d/r) A laminar velocity gradient — flow grows with perpendicular offset.
A divider with laminar flow — layers slide past each other.
crystallize if heat < ½: v += (node − p)·k; v *= 0.9 Snaps cool matter onto a lattice; melts and frees it when hot.
A "cool" section where matter snaps onto a lattice.
align v += (ĥ·|v| − v)·k, ĥ = neighbour-mean heading (or the body heading) Steers toward a heading, preserving speed — flock alignment.
A nav where particles flock to a shared heading.
wind v += curl(ψ)·S, ψ = sin(x·s + 0.2t)·cos(y·s − 0.2t) Divergence-free curl-noise turbulence.
A hero with divergence-free turbulence drifting through it.
cohesion neighbours: push if d < r₀, pull if r₀ < d < r₁ Short-range pressure + mid-range pull — surface tension.
A tag group that behaves like a droplet — a swarm with a skin.
pressure ρ = Σ W(d, h); v += −k·(ρ − ρ₀)·∇W (push down the density gradient) SPH density relaxation — incompressible even-fill via mutual repulsion.
A dense cluster that relaxes to an even fill, like a settling fluid.
hunt predator: v += seek(nearest prey)·S; prey: v += flee(nearest predator)·S Two-species pursuit — predators seek prey, prey flee predators.
A two-species swarm that chases and scatters — a living ecosystem.
spawn while engaged: emit S·2 particles/frame along the heading, each living ~90 frames A source [S] — creates matter along the heading, budgeted by a lifespan + pool ceiling.
A nozzle that jets matter into the field — a literal fountain or a star seeding the void.
link neighbours: e = d − L; v += ½k·(e/L)·û (holds rest length L = range·0.35) A Verlet distance constraint — ropes, chains, cloth, soft structures.
A cluster that holds together like cloth — a soft structure that ropes and drapes.
morph assign p → target t (hash of gx); v += (t − p)·k + jitter·(1 − arrived) Matter assembles into a mark / chart / logo — never words (§11).
A logo or chart that assembles from drifting matter — a mark, never words.
resonate modifier: scales sibling S by S(t) = 1 + sin(ω·t) Pulses its sibling forces with a time-varying strength.
Pair with attract: a well that breathes (pulsing strength).
spotlight modifier: gates siblings outside an angular cone of the heading A directional gate — confines sibling forces to a beam.
Pair with stream: a directed beam confined to a cone.
pigment on overlap: c_p ← mix(c_p, tint, rate); the colour advects with matter Conserved colour transport — matter takes on and carries a tint.
A section that stains passing matter its own colour, carried away.
fieldflow n̂ = netField/|netField|; v += (n̂·|v| − v)·k_steer + n̂·gain·a_accel, gain = S·(1 − d/r) Follow the field lines — steer onto and stream down the net field a body radiates.
A magnet or charge whose field lines the swarm threads, like plasma along a solar prominence.