Each confetti piece is a rigid flat plate falling through still air. Instead of a scripted wobble, its rotation and translation are coupled through real quasi-steady flat-plate aerodynamics: the angle between the plate's chord and its velocity vector (angle of attack Δ) sets both the drag/lift forces and an aerodynamic torque, and that torque changes the orientation that determines the next instant's Δ — a genuine feedback loop.
C_D(Δ) = C_D0 + C_D1·sin²Δ
C_L(Δ) = C_L1·sin(2Δ)
τ_align = −C_T·ρAL·V²·sin(2Δ)
τ_damp = −C_R·ρAL²·ω·√(V² + (ωL)²)
The dimensionless ratio κ = ρL³/m compares aerodynamic torque to rotational inertia. Small, light pieces (high κ) get pushed around by every gust of self-generated airflow and flutter — a rapid side-to-side rocking with little net rotation. Large or dense pieces (low κ) barely feel the aerodynamic torque relative to their own inertia and instead tumble — a steadier end-over-end rotation. This κ transition is the same qualitative result reported for real falling cards and leaves in unsteady-aerodynamics research.
- Piece size / mass — set the plate's chord length and mass, which together fix κ.
- Air density — scales every aerodynamic force and torque at once (thin vs. dense air).
- Launch speed — initial burst speed fired from the cannon at the click point.
- Click the canvas — fires a fresh burst from that point; drag to pan, scroll/pinch to zoom.