Same Y modifier

On the Tools menu click Snaps to select Same Y

SAME Y is a special modifier that aligns points horizontally with the reference point. First select a drawing or editing command, then SAME Y. CC3's prompt doesn't change. When you select the next point for the entity you are drawing, CC3 locks the point to the nearest point that lines up horizontally with the last point used in drawing or editing

Please see SAME X for examples.

Text equivalent: SAMEY