While the above curve inference handles a majority of sketched curves, we provide some additional features for users to create strokes that do not our curve types and settle ambiguous situations. Occasionally a user might wish to construct a shell projection curve with a straight line, or conversely a tangent plane curve with considerable curvature. As the tangent plane curve-type is a planar variation of a shell projection,we allow the user to toggle our default interpretations using the shift key. More precisely, if the algorithm were to choose a shell projection curve and the shift key was pressed, the result would be swapped with a tangent plane curve, and vice-versa. Users can explicitly indicate curve types by mode switching but our strength lies in presenting a pure sketching interface where our algorithm enables a creative workflow that is not impeded by consciously mode-switching prior to placing a stroke.