I need a 3d polygon between two cylinders

I asked a similar question earlier.
But I guess it wasn’t specific enough. I need to place two cylinders down as a first person controller. After that I need to select the two cylinders and place a polygon between the two.
That is basically what I need. If you have any questions ask.
Thank you.

Since you did not post code, I can just give you some logic. Given the position of the two cylinders, pos1 and pos2:

var midpoint = cylinder1.position + (cylinder2.position - cylinder1.position) / 2.0;
cube.position = midpoint;

Height is a bit trickier since the build-in cylinder with y scale of 1.0 is two units high.

cube.localScale.y = cylinder1.localScale.y * 2.0;