Function py

docs/app/js/sanddance-app.js:122078–122078

(x18, y17)

const addY = (y15)=>add(bounds.x1, y15);
const px = (x17, y16)=>ma * x17 + mc * y16;
const py = (x18, y17)=>mb * x18 + md * y17;
const addp = (x19, y18)=>add(px(x19, y18), py(x19, y18));
const addpL = (x20, y19)=>addL(px(x20, y19), py(x20, y19));
function boundContext(_, deg) {