From what I can tell, you can not change the angle of the line coming into the dots so if doesn’t fit your use, you can’t adjust it. Also, I have not found a way to key frame the line coming on the screen.

only if we could rotate the points so tangent can be controllable

PRE-SALE QUESTION: I will be using your arrow maker for highlights. Your video only shows the arrows going in a straight line. 1) Can I make a square or circle or triangle and hold it in that position for any number of seconds? 2) Can I control the speed of the arrow drawing? 3) Can I make the arrow blink after it is drawn for highlight?

Nice product.