[TC4] Link multiple violet things

[Knux14]

Hello guys,
I'm playing with TC4 but i'm stuck on the Infernal Furnace research. I can't link multiple of theses purple things, Here's a picture of what I get :

Can anyone explain me how it works ?
Thanks

 

[Yusunoha]

place unused runes between active runes if they start looping around.

 

[Exedra]

It has to be in a straight line, they can't branch.

 

[Tristam Izumi]

It has to be in a straight line, they can't branch.

This, a thousand times this.

This is actually the most common "beginner" mistake I see new players ask about. You have to have one continuous line connecting all the nodes. Pretend you're trying to draw a single line with a pen and you're not allowed to pick up the pen or backtrack.