Trying to create a beam in Godot Engine. How to do that?

Desired beam:

Try 1. Must be something like this. But it doesn't work

Try 2:
1. Fix a shader. Connect it to UV. 2. Use 2 crossed cubes with Z scale equal 0.00001. 3. Apply shader to those cubes

Try 3.

1. Replace TextUniform to ColorRamp 2. Remove ColorRamp from Diffuse socket

Now it looks great!