HEEEEEELP!!! Isolate length value.

Hi guys!
Do you know how to isolate a value in grasshopper?
I need a specific length value of variable line to be constant even when the line is changing its lenght...

I'll show you in the pictures.

I've copied the object by moving it vertically through L1 and horizontally through L2.
The value of L2 is depending by the width of the object, so when I decrease it to L3 the copied object is moving from its original axis.

I want to keep L2 constant so that the object axis are not changing.

Can someone help me?

thanks so much!!!!