for (sp in springs) {
    var p1:Particle = sp.p1;
    var p2:Particle = sp.p2;

    var rijx = p2.x-p1.x;
    var rijy = p2.y-p1.y;
    var rij = fastSqrt(rijx*rijx+rijy*rijy);

    var dThreshold = sp.restLength*sBreakYield;
    if (rij > sp.restLength+dThreshold) {
        sp.restLength += plasticity*(rij-sp.restLength-dThreshold)*dt;
    } else if (rij < sp.restLength-dThreshold) {
        sp.restLength -= plasticity*(sp.restLength-dThreshold-rij)*dt;
    }

    var lij = sp.restLength;
    if (lij > sBreakLen) {
        springs.remove(sp);
        continue;
    }

    var rijx = p2.x-p1.x;
    var rijy = p2.y-p1.y;
    var rij = fastSqrt(rijx*rijx+rijy*rijy);
    if (rij > 0) {
        rijx /= rij;
        rijy /= rij;

        var d = kspring*(1-lij*hInverse)*(lij-rij);
        var dx = d*rijx*.5*dt*dt;
        var dy = d*rijy*.5*dt*dt;
        p1.x -= dx;
        p1.y -= dy;
        p2.x += dx;
        p2.y += dy;
    }
}