How to create (guide)lines that meet atvanishing point out of the screen?

[pepr]

Hello to all,

I try to create the icon like this the correct way...



I did compose the image from the freely available SVG icon https://uxwing.com/box-icon/ The width of the stroke is not created by the line thickness (causing problems with buts and caps). All is drawn with no-width line as a complex shape like this:



The box uses two vanishing points. Because of that, putting two boxes together looks strange.

I would like to draw it from scratch. And I would like to learn how to work with vanishing points in Xara. My idea was to get the original cube and use the Guidelines layer to add lines that join in the two vanishing points. However, the vanishing point is quite far from the picture and it goes out of the page and even too up, out of the page stripe.

What is the correct approach?

Thanks and have a nice day,
Petr

P.S. I did Arrange -- Combine shapes -- Add shapes to put the two copies of the original together. Then I did remove the extra points that should not be there. I have to say, I should also search for the correct way to remove the extra points. Would that be the a good question on its own?