Soft Magnet
An interactive particle sphere that turns slowly on its own and gathers toward the cursor.
Soft Magnet is an interactive particle system written for the browser in plain HTML and JavaScript, drawn on a single canvas without any libraries. Sixteen hundred points form two nested spheres: a dense core of six hundred and a looser halo of a thousand around it. Every point is projected through a simple perspective camera, so those nearer the viewer grow larger and darker while the far side of the form recedes into a pale haze, and the whole figure turns about its vertical axis, the core orbiting half again as fast as the halo.
The cursor acts as a soft magnet. Points within its reach are drawn gently toward it, then pulled back to their orbits by a spring and slowed by damping, so a pass of the mouse leaves a brief wake that closes as the sphere settles. The behavior rests on a handful of constants for attraction, return force, friction and orbit speed, balanced over a week so that the sphere answers the hand without losing its calm, continuous rotation.