If there is possibility to add ability to connect more lines on one point and ability to make shapes share points (intersection).

You can, but at the moment it's not super intuitive. Here's an example recreating the scene on the right which you're interested in.
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You can, but at the moment it's not super intuitive. Here's an example recreating the scene on the right which you're interested in.
https://jsfiddle.net/jonobr1/31e27tpy/