**The Problem:**

**My Partial Solution:**

**D**through

**G**is easy:

vec3 forward = normalize(I-J); // direction from J to I vec3 right = cross(forward, vec3(0,1,0)); // direction from F to G G = J + (right * 2); // 2 = width/2 F = J - (right * 2);

I can use the same formula to compute **D** and **E**.

**Where I Need Help:**