Joints: a chain and a spring

using RecursiveAI.OneMath;
using RecursiveAI.OnePhysics;
using RecursiveAI.OnePhysics.Physics2D;
 
var world = new PhysicsWorld2D();
var anchor = world.AddBox(new Vector2F(0.2f, 0.2f), at: new Vector2D(0, 10), type: BodyType.Static);
 
// A chain of five links, each hinged to the one before, swinging from the anchor.
Body previous = anchor;
var links = new List<Body>();
for (int i = 0; i < 5; i++)
{
    var link = world.AddCapsule(0.15f, 0.5f, at: new Vector2D(0.5 + i, 10));   // radius, half length
    world.AddHinge(previous, link, new Vector2D(i, 10));          // the hinge point, in world coordinates
    links.Add(link);
    previous = link;
}
 
// A spring holds a box under a ceiling.
var ceiling = world.AddBox(new Vector2F(2, 0.2f), at: new Vector2D(8, 10), type: BodyType.Static);
var weight = world.AddBox(new Vector2F(0.5f, 0.5f), at: new Vector2D(8, 8));
world.AddSpring(ceiling, weight, new Vector2D(8, 10), new Vector2D(8, 8), 2f, 0.3f);   // 2 Hz, damping ratio 0.3
 
for (int step = 0; step <= 180; step++)
{
    if (step % 60 == 0)
        Console.WriteLine($"t={step / 60.0:F0}s  chain end {links[^1].Position}  weight y={weight.Position.Y:F4}");
    world.Step(1f / 60);
}

t=0s  chain end (4.5, 10)  weight y=8.0000
t=1s  chain end (0.715487866429612, 5.590997472172603)  weight y=7.9398
t=2s  chain end (-4.190456279087812, 9.45277669513598)  weight y=7.9390
t=3s  chain end (-1.8731370756868273, 6.337280875071883)  weight y=7.9390