a little something to help those searching for information on what those symbols mean hopefully this helps please delete if you feel it's superfluous or if not add pictures for quicker reference. ( not a demand just an option)
Constraints symbols fusion 360
Coincident : Two lines or shapes that lie exactly on top of each other.
Collinear : When three or more points lie on a straight line. (Two points are always in a line.)
Concentric : Two or more curves or arcs which have the same center point
Midpoint : The middle of. The point halfway along.
Fix/unfix : lock or unlock in position
Parallel : Two lines on a plane that never meet. They are always the same distance apart.
Perpendicular : At right angles (90°) to.
Horizontal/vertical : Something will snap left to right or up and down Not at an angle
Tangent : A line that just touches a curve at one point, without cutting across it.
Smooth : the opposite of rough not abrasive or rigid
Equal : same as or equivalent
Symmetry : identical or looking the same
If you're having trouble figuring out lines in geometrical terms I would suggest going to ( http://www.mathsisfun.com/definitions/ )
If you're unable to give a simple answer sometimes it means you don't understand well enough yourself and sometimes the desire to know overwhelms the fear of looking stupid.
