Function dot

docs/app/js/sanddance-app.js:69978–69980

(a, b)

    return out;
}
function dot(a, b) {
    return a[0] * b[0] + a[1] * b[1];
}
function cross(out, a, b) {
    var z = a[0] * b[1] - a[1] * b[0];
    out[0] = out[1] = 0;