In this pattern, 4 elliptical arcs.
From Oa to E1, ok
From Ra to Qa, ok
From Qb to d4a, the arcs radii are visually reversed (that is to say, Val has taken into account 1st radius instead of 2nd and vice versa)
From d4a to Ob, the arc does not reach Ob whereas the label mentions the right 2nd angle.