started with backend. We need a better datastructure. Relation between sensor and interface. Every sensor has always a interface? Yes I think so... I will meditate about it.
Drawing lines in Backend and creating blocks are possible now. Relations and Blocks are saved in localStorage. Next step is to get relevant data for the frontend. Every frontend is an interface with ID in URL. You come to the frontend via click on the link on the block of the ui-block.