Show Euler line on a draggable triangle
This was an amazing discovery two thousand years ago. The 3 center points in a given none-special triangle is bound to line up in one line. Check out https://en.wikipedia.org/wiki/Euler_line
You can use this demo program to get an intuitive view of any triangle that you like, how ever queer it is.
o change the shape by dragging any one of the vertices
o click one of the centers to toggle the lines passing it to show or to hide themselves